What's happening to CPU prices?!

c0d1f1ed

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This is getting stranger every time I visit my local store. Last month a Pentium 4 3.0 GHz was affordable, but a 3.2 GHz costed half as much more. Now, the 3.2 GHz dropped and the 3.4 GHz is twice as expensive. Soon, the 3.4 GHz will be affordable, but the EE version will still cost four times more!

But what's beyond the 3.4 GHz? There haven't been notable technological advances for more than a year. And Prescott isn't really mind-blowing. Soon all processors will be cheap as bread and you'll pay a fortune -literally- for something 10% faster than mid-end.

So where is this heading? Should we all start buying dual CPU systems, or go with the mighty Itanium? I need a really fast number-cruncher, but I don't want to sell my house for a few hundred MHz more...
 

Mephistopheles

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I agree, the prices on CPUs have been very crazy lately. I hope this is just a local thing that will dissipate, 'cause the tendency to put the fastest processor above, say, $700, is just pathetic. I mean, that's almost in the Xeon/Opteron price range......

<i><font color=red>You never change the existing reality by fighting it. Instead, create a new model that makes the old one obsolete</font color=red> - Buckminster Fuller </i>
 

TheRod

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That's the market!

There is people who pay much for TOP CPU's and there will always be. Why do you think you can buy DVD player for 40$ to 500$, because there si crazy people out there who think that price matter.

We all know (enthousiasts) that the difference in performance between a P4 3.2 and 3.4GHz is not worth the extra money. But, you know that people with lots money are willing to pay that extra cash, because they have it and they want to burn it.

--
Lookin' to fill that <font color=blue>GOD</font color=blue> shape hole!
 

Renegade87

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I love being on the trailing edge of leading edge technology. That's where all the bargains are. Bragging rights (while a powerful force in the universe) are for kids and in the end only make the greedy corporations fat and happy.

After the new i915/925 platforms are introduced with new P5 Prescott cores at 3.6GHz +, pick up that previously mentioned 3.4GHz Northwood at say $235 (or whatever) and slap it on a Abit IC7 Max3 with the Thermalright or Swiftech heatsink of or choice (did somebody say watercooling ?) and overclock that bad boy well over 4GHZ at a fraction of what it would cost to buy an i925 mobo, P5 CPU, DDR2 memory, and lets not forget that new BTX case you'll need to house it.

"Nuke em till they glow, shoot em after dark"
 

justaguy

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I agree wholeheartedly. I can't wait to upgrade my GF3 to a 9800 Pro sometime soon when they're dirt cheap.

Athlon XP 1900 (11x200) 42C (Load w/AX-7 & 8cm Tornado) - MSI K7N2 Delta - Corsair Value PC3200 - Gainward GF3 @ 250/550 - 80Gb WD 8Mb Cache -
 

c0d1f1ed

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I understand it's the market, but what's taking technology so long? We always used to have 'exponential' prices but never this steep. I can buy a 3.2 GHz for 300 €, but if I really have 600 € to spend, I only get 200 MHz extra! Things used to have been very different.

I also understand that dual-core processors are the future, but they won't appear before late 2005. So what will happen in the meantime? 3.6 GHz at 100 € and absolutely nothing beyond that? Ok maybe a 3.8 GHz EE for 1000 €. That's ridiculous!

Is it the right time to switch to dual-processor systems? 2.4 GHz Xeons are quite cheap and give a combined performance of 4.8 GHz. That's something I could start to use! Or is there a better way to get a system that performs equally?
 

TechMan

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For your own PC, it's OK to grab the trailing technology. Especially if budget is limiting. But for office use, insist for the best setup your company is willing to provide. That's how I ended up having AMD64 3000+ at work and PIII 667 at home.
 

P4Man

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> I can buy a 3.2 GHz for 300 €, but if I really have 600 €
>to spend, I only get 200 MHz extra! Things used to have
>been very different.

Not really. The only thing that has changed, is that in the past those €600 would have gotten you 7 or 33 Mhz extra, instead of 200 ;)

Seriously, throughout the years I've been watching this market, it has pretty much always been like this. Mainstream cpu's are priced relatively close to each other, and the fastest 2 or so speedgrades nearly double the price for no more than a few percent better performance.

>I also understand that dual-core processors are the future,
>but they won't appear before late 2005. So what will happen
>in the meantime?

The usual, higher clocks, faster busses and memory,..

>3.6 GHz at 100 € and absolutely nothing beyond that?

Top end part will *never* be €100. The cheapest they have been from intel was ~$400 or so, and that was when intel was caught with it pants down with the Athlon FX taking the performance crown, and the P4EE not being shipped yet.

>Ok maybe a 3.8 GHz EE for 1000 €. That's ridiculous!

Why ? How is it different as what it is now ? Fast forward a year or so, and you'll see the same thing, only dual core chips costing exponentially more than single core chips, while only offering a decent speedup in some apps (probably not gaming).

>Is it the right time to switch to dual-processor systems?
>2.4 GHz Xeons are quite cheap and give a combined
>performance of 4.8 GHz.

Depends entirely on the apps you run, but even in the best case, a dual CPU will not speed up 2x over a single cpu. Real world speedup range from 0% to 40%. For most uses, its a waste of money really..

= The views stated herein are my personal views, and not necessarily the views of my wife. =
 

Mr_Nuke

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I always said:" Don't buy the top notch, buy those a bit slower and yuo will save a lot of money" And I have been saying this since 2001 when I had my own PC. Since then I keep watching the prices since and it's never been different. The only problem now is the A64FX. There's only one on the production line at a time so I don't see how prices may go down on it
 

c0d1f1ed

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Seriously, throughout the years I've been watching this market, it has pretty much always been like this. Mainstream cpu's are priced relatively close to each other, and the fastest 2 or so speedgrades nearly double the price for no more than a few percent better performance.
True. Except for the fact that 2.8 to 3.2 GHz, which I consider high-end (consumer), now sells for prices well below 300 €. That used to be mid-end prices! I mean, these processors are really affordable. But paying twice as much doesn't give me anything extra, while one year ago there was really a significant performance difference, for this price difference.
Why ? How is it different as what it is now ? Fast forward a year or so, and you'll see the same thing, only dual core chips costing exponentially more than single core chips, while only offering a decent speedup in some apps (probably not gaming).
I cannot agree. Dual-processor systems offer twice the performance of single-processor systems in many applications. I don't care about games and besides, they should learn how to use multi-threading. I don't expect dual-core processors to be much different. If a low-end dual core 2 x 3.0 GHz costs twice as much as a high-end single-core 4.0 GHz I would buy it! There's just no alternative like that these days. EE processors are ridiculously slow once you've seen the price tag.

I'm not expecting a linear performance / price curve, not at all. But the current curve is more exponential than ever. What's even worse is that I don't see any changes for at least a year. Moore's law is no longer true!
 

P4Man

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>True. Except for the fact that 2.8 to 3.2 GHz, which I
>consider high-end (consumer) ..<snip> .. I mean, these >processors are really affordable

Well, if they are so affordable, I guess they are no longer that high end, are they ? "Really high end" would be the 3.4 (3400+), and 3.2EE, 3,4EE (AFX) versions then. Really not different from say ten years ago when a (once highend) Pentium 90 and 100 Mhz would be affordable (well below 300 value adjusted euro's), and the 120 and 133 MHz parts would not.

>while one year ago there was really a significant >performance difference, for this price difference.

Not more "significant" than between a P4 3.2C and a 3.4EE or a A64 3200+ versus a FX53.

>Dual-processor systems offer twice the performance of
>single-processor systems in many applications

Name me one (more or less common) real world app that speeds up by a factor 2x running on a 2 way system. 50% would already be very "SMP friendly", 25% more typical.

>and besides, they should learn how to use multi-threading.

LOL. Yeah, its so easy.

Some problems just don't lend themselves to SMT, because they are linear by their very nature. Think of it this way: if I can look up a word in the dictionnary in 10 seconds on average, if I could work (read, think and turn the pages) twice as fast, I could do it in 5 seconds. How long do you think it would take 2 persons (as fast/slow as me ) ? Or even 10 ?

What you are expecting from developpers is the equivalent of: find me a way to look up a word in the dictionnary twice as fast using twice as many resources (people). Good luck !

A better analogy would be software development itselve; if you've ever worked on a big project, you'd know doubling the resources (number of developpers) *never* halves the development time, not even anywhere near that. Beyond a certain point it will even *increase* it.

> If a low-end dual core 2 x 3.0 GHz costs twice as much as
>a high-end single-core 4.0 GHz I would buy it!

Then go ahead and buy a dual 1.5 GHz Xeon ($69 pricewatch), its definately cheaper than a single cpu highend system. However, it won't be (nearly) as fast either.

>I'm not expecting a linear performance / price curve, not
>at all. But the current curve is more exponential than
> ever.

You mean like when a 166 Mhz Pentium costed $300, a Pentium 200 ~$600, a 180 MHz Pentium Pro ~$1.000 and a 200 Mhz one ~$2.000 ?

>What's even worse is that I don't see any changes for at
>least a year.

Thats funny, I haven't sees any significant changes over the last 15 years either.. Hmmm... coincidence ?

>Moore's law is no longer true!

Moore has *NOTHING* to do with it. Its about transistor densities doubling every 18 or so months, and as such, its still as true as ever, with no change for the foreseeable future either with multicore chips and huge caches on their way. I'd even WAG GPU's are outperfoming Moore's "law" by a big margin.

= The views stated herein are my personal views, and not necessarily the views of my wife. =
 

c0d1f1ed

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Really not different from say ten years ago when a (once highend) Pentium 90 and 100 Mhz would be affordable (well below 300 value adjusted euro's), and the 120 and 133 MHz parts would not.
That was between 20 to 50% clock increase. In other words, you would be comparing 2.8 and 3.2 GHz with 3.8 and 4.2 GHz! Really not different?
Not more "significant" than between a P4 3.2C and a 3.4EE or a A64 3200+ versus a FX53.
Please explain. I really fail to see the solid 50% performance increase there. Besides, you are comparing consumer market with 'extreme' and server market here. 3.2 GHz is the top of the consumer market now, and it's affordable. Nothing above it, not even 10%, although I'm really still looking for that 50%. That's what I've been trying to say here.
Name me one (more or less common) real world app that speeds up by a factor 2x running on a 2 way system. 50% would already be very "SMP friendly", 25% more typical.
Maya. MATLAB. Visual C++. PhotoShop. Oops, you only asked one example...
Some problems just don't lend themselves to SMT, because they are linear by their very nature. Think of it this way: if I can look up a word in the dictionnary in 10 seconds on average, if I could work (read, think and turn the pages) twice as fast, I could do it in 5 seconds. How long do you think it would take 2 persons (as fast/slow as me ) ? Or even 10 ?
You should learn how to use multi-threading as well. I'm not talking about one 'dictionary lookup', I'm talking about several dozen. And you -can- do that twice as fast with twice as many people. Would you rather run the Google search engine on single or dual processor systems?
What you are expecting from developpers is the equivalent of: find me a way to look up a word in the dictionnary twice as fast using twice as many resources (people).
No. I'm expecting them to identify threadable operations. Things that can be computed independently. Even in a very 'linear' algorithm, instruction parallelism is around 20. So current (single) processors absolutely don't execute it optimally. I'm not saying it will be easy, but programmers will have to take advantage of multi-threading sooner or later. It's inevitable that future processors will be multi-core, multi-HT. It costs too many transistors to get another 5% of linear performance increase.
A better analogy would be software development itselve; if you've ever worked on a big project, you'd know doubling the resources (number of developpers) *never* halves the development time, not even anywhere near that. Beyond a certain point it will even *increase* it.
If you've ever worked on a big project, you'd also know that making everybody work twice as fast (or efficient) has its limits too. At one point, better soon, you have to double the number of employees. Currently processors are still one-man companies. I really know that doubling resources isn't the silver bullet but now they're not even trying!
Then go ahead and buy a dual 1.5 GHz Xeon ($69 pricewatch), its definately cheaper than a single cpu highend system. However, it won't be (nearly) as fast either.
I know there's overhead involved, that's why I would only consider buying dual 2.0 GHz or higher. 2.4 GHz Xeons still have a nice price and come with Hyper-Threading. On optimized software it will run faster than a 4.0 GHz.
Thats funny, I haven't sees any significant changes over the last 15 years either.. Hmmm... coincidence ?
I was talking about the future, not the past. It's clear to me that single-core technology has reached a wall. Sure, they'll still have 4.0 GHz by 2005, but nothing really spectacular. Speaking of spectacular, the newest GPUs are -twice- as fast as their predecessors, doubling the number of, yes, threads. I realize it's the ideal parallelizable algorithms but many applications have bottlenecks that are just as computationally intensive and parallel.

It simply won't be effortless any more for programmers to take advantage of new processor capabilities...
 

P4Man

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> That was between 20 to 50% clock increaseIn other words,
>you would be comparing 2.8 and 3.2 GHz
>with 3.8 and 4.2 GHz! Really not different?

No, not that different. Sure, jumps in clockspeed have reduced as we got more models -I mean, we have how many actual models ? 2,2.2,2.4,2.6,2.8,3.0,3.2,3.4, most in both 400, 533 and 800 MHz fsb's, as Celerons, P4s and P4EE's, with and without HT, SSE3,... there has go to be over 30 different variants if not more. In the old days you'd just have Pentium 75 (low end, like celeron), 90/100 mainstream, and 120/133 high end. So obviously the difference between mainstream and a one-step faster cpu would be bigger. But if you look at the product range and its pricing curve, you wouldnt see much if any difference. I would say 2.8 is mainstream now, which is 20% slower (clock) than the "normal" high end the 3.4C/E, and the uber/ultra EE would add another 10%performance (L3 cache). That is pretty much identical to the Pentium 100 being 20% slower than the 120, and the 133 adding a bit on top. You do realize the Pentium 133 was more expensive than the Pentium 4 3.4 EE when it was launched ? $935, 10 years ago.

Here is a good link for you:
<A HREF="http://www-ra.phys.utas.edu.au/~dr_legge/chip_prc.html" target="_new">http://www-ra.phys.utas.edu.au/~dr_legge/chip_prc.html</A>

>Please explain. I really fail to see the solid 50%
>performance increase there

I fail to see a solid 50% performance increase between a Pentium 100 and a 133 as well. And 30% would be more or less the difference between a 2 GHz A64 3000+ (mainstream) and a 2.4 GHz Athlon 64 FX or between a 2.8 GHz P4C and a 3.4 GHz EE.

>Maya. MATLAB. Visual C++. PhotoShop. Oops, you only asked
>one example...

Found no benchies for Matlab, but I really can't consider it a typical app either even if it would somehow reach anywhere near 100% speedup.

<A HREF="http://www.gamepc.com/labs/view_content.asp?id=wsapps&page=5" target="_new">Maya</A>: <b>39%</b> increase going from 1 to 2 (otherwise identical) Athlon 2100+'s.

<A HREF="http://www.gamepc.com/labs/view_content.asp?id=wsapps&page=7" target="_new">]C++ </A> a solid <b> 7% </b> improvement.

<A HREF="http://www.gamepc.com/labs/view_content.asp?id=thunderk7x&page=5" target="_new"> Photoshop 7 </A> impressive <b>14%</b> speedup.

Oops, I only asked for one indeed. None of your examples even seem to reach my optimistic 50% number.

> And you -can- do that twice as fast with twice as many
>people.

Not if you don't have twice as many dictionnaries and twice as many queries to run as well. And not if one of the searches depends upon the result of the other.

> I'm not saying it will be easy, but programmers will have
>to take advantage of multi-threading sooner or later. It's
>inevitable that future processors will be multi-core,
>multi-HT. It costs too many transistors to get another 5%
>of linear performance increase.

I don't disagree with you actually, its just not a silver bullet, and horizontal scaling (SMT, CMP,.) just can't replace vertical (clock/IPC) scaling for every problem. It also shifts the burden from hardware design/manufacturing to software design, something that rarely pays off. They should go hand in hand. A dual core 1.7 GHz willamette would be a poor substitute (performance wise, desktop workloads) for a 3.4+ GHz P4.

>If you've ever worked on a big project, you'd also know
>that making everybody work twice as fast (or efficient) has
>its limits too. At one point, better soon, you have to
>double the number of employees.

Doubling the timetable is a much more efficient solution :)

>Currently processors are still one-man companies

Not really, they have multiple execution units, and its already hard to write code to use those efficiently.

> 2.4 GHz Xeons still have a nice price and come with
>Hyper-Threading. On optimized software it will run faster
>than a 4.0 GHz.

Precious few, if any apps would. You might get twice the throughput running two (or 4) instances of SETI client, but for anything more complex, or speed and not throughput oriented, it won't be better. Don't forget you are not doubling memory bandwith (in fact, in your example you would decrease it by 75%/ cpu !), you are not reducing memory or cache latency either. Opteron is an exception where memory bandwith would scale with the number of cpu's but only using NUMA aware OS+apps, and even then you are increasing latency.

>I was talking about the future, not the past. It's clear to
>me that single-core technology has reached a wall.Sure,
>they'll still have 4.0 GHz by 2005, but nothing really
>spectacular.

Spectacular like what ? Like going from 100 to 200 MHz in two years ? Or 1.5 to 3 Ghz in 2 years ? Or 3 to 4 Ghz in one year ?

If there is any wall we are hitting, its not potential single threaded performance increases, but a thermal wall, and guess what, a dual core chip will roughly consume twice as much as a single core chip.

Obviously, we will see multicore chips in the future, but for somewhat other reasons as what you imply: smaller processes finally give us cores small enough to economically produce several of them in one chip (<200mm²). That used to be impossible. just like HT, it will help especially running several programs or process simultaneously, but it won't speed up most things by more than 30%.

A very interesting quote and link in this context:

For over a decade prophets have voiced the contention that the organization of a single computer has reached its limits and that truly significant advances can be made only by interconnection of a multiplicity of computers in such a manner as to permit co-operative solution...The nature of this overhead (in parallelism) appears to be sequential so that it is unlikely to be amenable to parallel processing techniques.

This is a quote by Gene Amdahl from <b>1967</b>.
<A HREF="http://home.wlu.edu/~whaleyt/classes/parallel/topics/amdahl.html" target="_new">Amdahl's law </A>

= The views stated herein are my personal views, and not necessarily the views of my wife. =
 

BigMac

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c0d1f1ed and P4man

Just wanted to thank you for a very educational thread. I hope it's not over yet :smile:



BigMac

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Mr_Nuke

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In order to double the performance using 2 CPU's, you need everything doubled overall: twice the Mhz of the single CPU, twice the bandwidth, half the latencies,etc. Mem bandwidth condition has been completed, but what about HDD bandwidth? You're right. It's still a long time until that law can finally be contradicted.
 

c0d1f1ed

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http://www-ra.phys.utas.edu.au/~dr_legge/chip_prc.html
Thanks for that link, because it proves part of what I'm saying. Look at the Pentium III prices of August 2000. The 1000 MHz costed 669, and the 700 MHz costed 193. Translating that to todays situation, a 3.0 GHz could cost 669, and a 2.1 GHz costs 193. Yeah right. A 3.0 GHz is affordable now, while nobody would pay 193 for 2.1 GHz! And while paying 400 extra those days gave you 300 MHz extra (42%), it's still ~300 MHz (10%) you get when paying 400 extra for todays processors as well!

I do realize these numbers can be pushed and pulled a bit, but I can't help this feeling I have with today's market situation. Maybe I'm the only one who sees it but high-end processors are really affordable and for one notch higher you pay a fortune. And I blame it on the technology wall.
I fail to see a solid 50% performance increase between a Pentium 100 and a 133 as well.
You mentioned 90 MHz as well...

Anyway, this might be an eye opener for you (and many other): <A HREF="http://images.digitalmedianet.com/2003/03_mar/editorials/smack105030326/1-chart.jpg" target="_new">Multiprocessing Performance</A>

What we see here is three similar applications (image processing) running on single and on dual 1 GHz G4's. Although they all did the same type of test, the best software did the job nearly twice as fast, while the worst didn't show significant benefits at all.

This learns us that for multi-processor (or multi-core) systems you really can't say it's 25% faster, or any other fixed percentage. It -all- depends on the software. And this example clearly shows that a lot can be won just by properly optimizing the application for multi-threading.

Note that we would be talking about 5.5 GHz in Pentium 4 terms here! It will take some effort from the developers, but isn't that worth it? It's a fact that developers have become lazy because current processors take care about everything like scheduling and precaching. But I firmly believe that if all those transistors would be used for execution units and the programmer (and compiler) would really make use of that architecture, we'd be far beyond current performance levels. Note that there's a parallel with VLIW processors like the Itanium. They use parallelism explicitely and even at low clock frequencies their performance blows everything away -if- the software is optimized for it.

Once the bigger part of processors are multi-core, developers will really start to learn how to use it, and getting a performance increase close to the number of cores won't be an exception. Current developers nearly all work on single-processor systems so they simply don't see the benefits of optimizing for multi-threading.
 

P4Man

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>Thanks for that link, because it proves part of what I'm
>saying. Look at the Pentium III prices of August 2000.

Thats a terrible datapoint. The 1 GHz Pentium III was a phantom chip, and mostly a PR launch to counter AMD's 1GHz and 1.1,1.2 GHz Athlons; but for practical reasons let alone revenue, it just didnt exist. Out of ten years of cpu pricing history, you pick the one (arguably only) moment where intel was lagging AMD in the clockrace and where they could not play their normal pricing game. It really doesnt prove what we are seeing now is a trend break.

>Translating that to todays situation, a 3.0 GHz could cost
>669, and a 2.1 GHz costs 193

No, translating that to today, it could mean a 3.4 (which is the top banana now, not the 3 GHz) would cost $669 and the 2.4 GHz (700/1000 x 3.4) would cost $193. They are both slightly cheaper than that, but close enough to match the pattern of even those days. And as I said, you could not have picked a less representative datapoint.

> Maybe I'm the only one who sees it but high-end processors
>are really affordable and for one notch higher you pay a
>fortune.

Like always. And you insist on calling the 3 GHz part "high end", while really, even if its a fast chip, its trailing bleeding edge by a fair ammount. 3GHz parts have been out for over 18 months. The 3.4 EE has a 12% higher clock, and with the extra cache it performs roughly like a 3.6 would, giving it a 20% lead over the 3.0. The FX53 would be ahead even further. If you look at that link I provided, at most points in time, if you'd pick the fastest cpu, look at its price, and compare it to the mainstream ones (being ~20% slower), you'd see a very similar pattern. I'm sorry, this is nothing new. No offense, but how long have you been watching this industry ? Something tells me you're a bright fellow, but not into this market for very long. I've been watching it for 15+ years, and the more things change, the more they stay the same. IF anything changes, its that overall prices have dropped, and you only need stiffer competition and much higher volumes to explain that.

>Anyway, this might be an eye opener for you (and many
>other): Multiprocessing Performance

LOL ! That is the best you could come up with ? They compare a single CPU *laptop* most likely using 100 MHz ram with a dual cpu desktop using PC133. Even there, the "best" multithreaded software, performing a type of workload that is probably close to the best case scenario for SMP, and yet it doesnt even come near to your 100% speedup claim.

I understand your point about some software being written to take better advantage of SMP or CMT, but what really matters is overall performance.

Its nice to see a 70% speedup on dual processors (using faster ram, and God knows what else is different between the systems, so say maybe 50-60% on identical cpu's), but what good does that do when that same software is 2x to >5x slower than competing packages ? Here, this may be an eye opener for you:

<A HREF="http://www.emedialive.com/Articles/ReadArticle.aspx?ArticleID=8066&PageNum=5" target="_new">http://www.emedialive.com/Articles/ReadArticle.aspx?ArticleID=8066&PageNum=5</A>
<A HREF="http://www.emedialive.com/Articles/ReadArticle.aspx?ArticleID=8066&PageNum=2" target="_new">http://www.emedialive.com/Articles/ReadArticle.aspx?ArticleID=8066&PageNum=2</A>

So is Final Cut Pro really such a fine example of good coding ?

>This learns us that for multi-processor (or multi-core)
>systems you really can't say it's 25% faster, or any other
>fixed percentage. It -all- depends on the software

I just barked at your 100% claim, and pretty much proved its incorrect. I said it ranged from 0-30% on average, up to around 50% on SMP friendly jobs (like rendering). Its ironic your links seem to support this claim, and you have failed to give me even one counter example of a 100% speedup.

You can blame developpers all you want, but reality is what it is. A dual cpu machine isnt nearly twice as fast as a single cpu machine. And no ammount of clever coding is ever going to make that happen. As it is, using the most clever compilers and coders, its already nearly impossible to make optimal use of *one* cpu's execution resources. If you doubt that, try running whatever cpu intensive app it is you use, look at the processor temperature. Now compare it to the temps you are seeing running something like BurnK7 which was designed specifically to max out all execution resources on a K7. HUGE difference.

Or another example: hyperthreading. All HT really does is try to make better use of the execution units of the P4, and fill pipeline bubbles. If your code was somehow magically close to 100% optimal, HT would not change a damn thing.

OTOH, a SMP machine can have (nearly) twice the throughput, (running several processes), which is one of the reasons you have been seeing SMP in servers for decades. But typical server and desktop workloads are really different worlds.

= The views stated herein are my personal views, and not necessarily the views of my wife. =
 

Mr_Nuke

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It'shard to imagine a 100% speedup. Like, you need everything double in terms of performance. As I previously stated, youneed twice the freq.(OK), twice themem bandwidth(OK for Opterons w/ proper OS),twice the HDD bandwidth(not OK), half the latencies - mem and cache(not OK) and all this talking in terms of hardware.
in software terms it comes like this: the program yourun must be able to use both CPU's equally(if it uses,let's say 97% of a single CPU, then it must use 97% of each CPU), it also has to transfer data from one CPU to the other w/o any sort of latency, wich is not the definition of multi-CPU systems, and also the bus between the CPU's has a limited bandwidth. So applications might benefit from multi-threading, but never reach that 100% speedup. Multi-threading is more usefull when multitasking, but you're talking about singletasking. Sorry.
 

P4Man

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Hmmm.. your logic is slightly flawed. If you double frequency, half latencies, double bandwith, double I/O, you'd get exactly twice the performance with just one cpu :)

= The views stated herein are my personal views, and not necessarily the views of my wife. =
 

c0d1f1ed

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Thats a terrible datapoint. The 1 GHz Pentium III was a phantom chip, and mostly a PR launch to counter AMD's 1GHz and 1.1,1.2 GHz Athlons; but for practical reasons let alone revenue, it just didnt exist.
Very well, then take Q3 1997 and compare 3.4 GHz - 2.4 GHz with 233 MHz - 166 MHz. Or Q4 1998 where you can compare it with 450 MHz - 333 MHz. Can you show me a date where the situation was 'worse' than today? That would really show me that it's all just a temporary thing.

Either way, I never said the current market situation is totally abnormal. I just see a small trend and if it continues like this I do believe there is reason to worry about current technology. In one of the other threads here I read about oxide layers being only 6 atoms thick! I can imagine this is very close to what is physically possible, while still having a production process that is, well, productive.

That's why I also believe that new architectures will soon be required, and to make more efficient use of the available transistor, much of the effort will shift to the programmer.
Something tells me you're a bright fellow, but not into this market for very long. I've been watching it for 15+ years, and the more things change, the more they stay the same.
Well my first CPU was a Z80 which was one of the first affordable consumer products. I was very young then but I've certainly seen the whole Pentium evolution in detail. But it's only about half a year ago that I started to notice that the performance to price ratios showed some weird behaviour. And in the last few months my local store kept dropping the prices of first 2.4 GHz, then 2.6 GHz, 2.8 GHz, and now 3.0 GHz to a really affordable level. In the meantime, no new processor had appeared and the 3.2 GHz remained almost steady at three times higher price. The picture is a bit different when you add the Prescott and EE models, but still I found it very remarkable how fast these prices dropped, while keeping the others really high. I can clearly see this wall they're hitting around 3.2 GHz.
They compare a single CPU *laptop* most likely using 100 MHz ram with a dual cpu desktop using PC133. Even there, the "best" multithreaded software, performing a type of workload that is probably close to the best case scenario for SMP, and yet it doesnt even come near to your 100% speedup claim.
Good point. The notebook has a slower memory interface. But I think it would be fair to assume that this causes a difference smaller than 10%, because that's what the After Effects software loses. So I also wouldn't be terribly wrong if Final Cut Pro still performed more than 55% higher in a dual processor configuration with PC100. There is no way such a gain could be achieved by doubling the transistor count of a single processor. And memory bandwidth is cheap so 70% is still realistic. Granted, it isn't 100% either, but I know a lot of people would really want to pay more than double, for 55-70% performance increase. Besides, 70% is actually very close to 100%: the difference in execution time is only 17%!

Anyway it's an illustration that programming technology and processor technology should cooperate to reach new performance levels. We've seen the same thing with SIMD technology (MMX and SSE). First they didn't offer any real-life speedup at all, because no programmer used it (or badly, like AoS) and it took years before consumers saw the benefits. But gradually and silently more applications made use of it and now some algorithms run up to four times faster with it! Multimedia players with low CPU utilization would be unthinkable without MMX and all 3D games would be processor limited without SSE. What I'm trying to say is, processor architecture really matters, and programmers will have to make efforts to benefit from it.

Last year I wrote an instruction scheduler for a compiler back-end. The results were totally dissapointing, and it wasn't my fault. It was the processor that already does instruction rescheduling, register renaming, memory prefetching, etc. Now imagine all the transistors for this technology were used to double execution units, and I used my software scheduler to do the same things the processor did. That would easily give me the same 55-70% performance increase, but now without extra transistors! The only drawback would be that unoptimized software would run slower. Like I've said before this is the approach taken by VLIW processors like the Itanium, and it works. I do realize though that it would take many years to migrate all legacy x86 applications to such new architecture, but it's inevitable...

I don't know if anyone realizes this but more than a dozen Katmai cores fit into a Prescott. And on .09 micron technology, they could be clocked at around 2 GHz (comparing with Coppermine and Tualatin). That's 96 GFLOPS using SSE! The new XBox will take a similar approach, with three cores at 3.5 GHz. Game programmers will have to learn SMP soon, and others will follow...
 

P4Man

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>Either way, I never said the current market situation is
>totally abnormal. I just see a small trend

Very small :)

>and if it
>continues like this I do believe there is reason to worry >about current technology.

That is a bit far fetched. There are more obvious explications, like competitive pressure from AMD, and the fact Intel indeed has problems scaling Netburst. You could maybe conclude Netburst (or more specifically, Prescott, since I believe a 90nm northwood would still have quite a bit of headroom) is hitting a wall, but I would not generalize this to conclude single threaded performance is hitting a brickwall. IBM and AMD seem to have no nig problems (yet ?) scaling up ST performance of their chips.

Sure, its getting more difficult, and mostly, more expensive, but the same doom scenerio has been predicted with each new process shrink, including 80 and 50µm shrinks in 1993. Pardon me for not holding my breath just yet.

>That's why I also believe that new architectures will soon
>be required, and to make more efficient use of the
>available transistor

What makes you think multicore is the only way to use those ever increasing transistor budgets ? God knows how many 486 cores you could fit on a 200mm² 130nm die, yet no one is doing it.

> There is no way such a gain could be achieved by doubling
> the transistor count of a single processor.

I disagree. Seeing something as "trivial" as SSE2, which accounts for maybe 2% of the diesize can achieve comparable speedups in cherrypicked apps... I also think these kind of highly paralellizable (word ?), FPU intensive workloads( rendering, video encoding,..) will more and more be offloaded to the GPU anyway, which is far better at those kind of things.

>Anyway it's an illustration that programming technology and
>processor technology should cooperate to reach new
>performance levels. We've seen the same thing with SIMD
>technology (MMX and SSE). First they didn't offer any
>real-life speedup at all, because no programmer used it (or
>badly, like AoS) and it took years before consumers saw the
>benefits

There is one major difference: MMX/SSE code can be generated automatically by the compiler, the developper hardly has to do anything special. And if not, its a rather trivial change to your code, and its really not in the same league as creating efficient multithreaded code. And if you think MMX or SSE is a bad example because of the "limited" scope of apps that can benefit, then consider AMD64 which costs <5% of the diesize and can increase performance anywhere from 0 to 20% on average, with spikes up to 100%.

>and now some algorithms run up to four times faster with >it!

LOL, exactly. Using something that is hardly a few percent of the diesize (as opposed to doubling it) and which requires nearly no effort from the developper besides setting the -mfpmath=SSE or -mmmx switches of their compiler. I thought you where the one claiming single threaded performance scaling was dead ?

>I don't know if anyone realizes this but more than a dozen
>Katmai cores fit into a Prescott

Thats just not true. Acording to sandpile, katmai was a 128mm² part on 25nm. That would mean roughly 80mm² on .18, 50nm on .13 and 30nm on .09. That is ~2.5x smaller than prescotts core which is 112 nm, a big part of which is used for L2 cache (don't forget, Katmai had no ondie L2 !!). You could fit at most 3 Katmai cores on Prescott if you want to keep the cache, and we all know Prescott contains countless apparently unused or at least unexplained 'phantom' transistors. Compare it to Northwood, and you could maybe fit in 2 cores at most. Never "more than a dozen". How did you get that number ? Just transistor count ? if so, that is bogus obviously, since cache transistor are MUCH more dense, and much cheaper than logic transistors.

> Like I've said before this is the approach taken by VLIW
>processors like the Itanium, and it works.

Well, I'd argue the "it works" part, because IMHO, it doesnt work except for FP which has very little to do with this discussion (since FP is "easy" too achieve). For integer performance (and even for FP), if you look at performance/mm², performance/transistor it trails x86 by a rather huge margin. You do realize Madison 6M is more than 3x as big as a Xeon (Prestonia) on the same process, and has nearly <b>10x</b> as many transistors ? So, are you still sure its good idea to ditch all that reordering logic to save a couple of hundred thousand transistors ? And if you look at the floorplan of Madison 9M and even Montecito, you may notice the core only occupies ~15-20% of the die estate in size and a tiny fraction in transistor count, so even using the EPIC approach, for a cpu designed only for the server market, it seems intel thinks there are still better ways to spend transistor than double the number of cores..

= The views stated herein are my personal views, and not necessarily the views of my wife. =
 

c0d1f1ed

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Very small :)
I must agree. But did you find that date yet in the table that showed a worse scenario than today?
Sure, its getting more difficult, and mostly, more expensive, but the same doom scenerio has been predicted with each new process shrink, including 80 and 50µm shrinks in 1993. Pardon me for not holding my breath just yet.
Sure, I understand you think it will all just magically work out, again. Oxide layers can be six atoms, then three, then one, then sprinkled here and there... I'm sure you get my point. Current technology is hitting -phycical- limitations, not just manufacturing issues. I think it's a bit naïve to assume that if a CPU technology has continued to grow steadily for the past fifteen years, it will grow forever. There will undeniably still be progress, so you might be right we don't have to hold our breath yet, but when do you expect to hit the wall then? One year, five years, another fifteen year?
What makes you think multicore is the only way to use those ever increasing transistor budgets ? God knows how many 486 cores you could fit on a 200mm² 130nm die, yet no one is doing it.
I believe so, because many algorithms are highly parallelizable. Name one application that would never run faster on multiple processors.

Noone is doing it, because up until now it was possible to use smaller processes and increase the number of transistors solely to increase the clock frequency. AMD's less radical approach shows that this is not the only way to increase performance. IPC matters, and soon they'll realize TLP matters as well. Intel has constantly strived to make unoptimized x86 code run faster, with a lot of succes. But they can't keep optimizing hardware till infinity, wasting more and more transistors, just to make sure no new effort has to be made by the programmer to make it run faster.

Processor performance is now up to a level where 'office' applications programmers don't have to worry about optimizations, but other programmers are -willing- to take advantage of new architectures.
I disagree. Seeing something as "trivial" as SSE2, which accounts for maybe 2% of the diesize can achieve comparable speedups in cherrypicked apps...
Thanks for agreeing. :smile: SSE is part of the new architectural changes I'm takling about. They require little extra transistors, but a lot of effort from the programmer to take advantage of.
MMX/SSE code can be generated automatically by the compiler, the developper hardly has to do anything special.
ROFLMAO. Give me a minute to get back onto my chair ok... Sorry, don't take it as an insult please.

Compilers, even the ones that claim support for vectorization, are lousy at using SIMD (without "the developper doing anything special"). It's not because these compilers have been badly written, it's just that SIMD technology, and the way Intel implemented it, isn't suited for automatic compilation. You have to redesign algorithms to make use of it. I can even show examples of C code where Microsoft's compiler produced faster code using the FPU, than Intel's compiler using SSE.
And if not, its a rather trivial change to your code, and its really not in the same league as creating efficient multithreaded code.
Well it won't surprise you now that you're wrong again. To really make efficient use of it one has to write the assembly code manually. There are lots of tools to help, like intrinsics and inlining, but either way I consider that "special effort". And writing multi-threaded code really isn't -that- hard. I'm currently working on a camera surveillance system where several cameras are shown on one monitor, using motion detection to pick the most interesting ones to display. It's really 'natural' to use a thead per network connection, per detection routine and per image panel. Although in this case it's not really because of performance reasons, I'm just saying that multi-threading isn't harder than the MMX optimized detection routine. It's just on a different (higher) level. I'm very confident that it can be used relatively easily for optimization purposes when using multi-processor systems.
Thats just not true. Acording to sandpile, katmai was a 128mm² part on 25nm. That would mean roughly 80mm² on .18, 50nm on .13 and 30nm on .09. That is ~2.5x smaller than prescotts core which is 112 nm, a big part of which is used for L2 cache (don't forget, Katmai had no ondie L2 !!).
The size of the process is indicated by the gate size. It can't be used directly to tell how many transistors fit onto it. Katmai has 9.5 million transistors, Prescott has 125 million (75 excluding the cache). In all fairness, it shows that Prescott is very wasteful with transistors for nearly the same instruction set, and with a simpler architecture and slightly lower clock it could have had many more execution units. Let's not forget the Katmai cores would have some redundant duplicated logic.
...and we all know Prescott contains countless apparently unused or at least unexplained 'phantom' transistors.
And these phantom transistors are going to do what, double performance? If it's 64-bit support then it certainly won't, and if it's Full Scan technology then they could have omitted it when using a more predictable simple multi-core architecture.
How did you get that number ? Just transistor count ? if so, that is bogus obviously, since cache transistor are MUCH more dense, and much cheaper than logic transistors.
40% of Prescott transistors (cache) is on 30% of its die space. This tells me cache fits on 75% of logic space. Well if that's your definition of "MUCH more dense" then I can still fit in nearly a dozen Katmai cores. And it would only take a tiny bit of extra space to add a serious L2 cache. But it wouldn't have to be huge because a thread can be halted a bit to fetch the data, while other threads continues to fill all pipelines. Anyway I'm not saying performance will be a dozen times higher, but still really very much worth it.

The last few articles at Ace's Hardware are closely related to this discussion: <A HREF="http://www.aceshardware.com/list.jsp?id=4" target="_new">CPU Architecture & Technology</A>. And if The Inquirer is correct then also Intel is looking at other architectures: <A HREF="http://www.theinquirer.net/?article=15768" target="_new">Intel’s Potomac team gets dissolved</A>.

Are you still sure that current single-processor technology is not in trouble?
 

trooper11

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Well Intel isnt looking at 'new technologies' its still pased on an old core, the p6. It seems they have decided to concentrate efforts on thier p-m chips to bring them to desktops. i think its a good idea, the p-m line has alot of promise so hopefully they can pull that off.

This discussion has gone out into outer space somewhat from the orginal topic, but its ok lol.

I dont think the high end prices of cpus have any bearing on the market going up in price as a whole. There have always been high prices for new chips, its not new. If you want to see the condition of the market, look at the mid-low end segments. To me, they look about the same as its always been, there are no upturns in cost for the consumer in relation to past products.

As far as the future of cpus, I dont think anyone here can say where it will head. Although I must say, it seems amd at least will push for dual cores, so it would seem they are embracing multithreaded environment as a way of pumping up performance. Intel just seems to be in a transition phase with no real plan as of yet, still trying to figure itself out. We hear a bunch of rumours about intel right now, they jsut seem busy atm lol.

I dont think its a question of wether single or multi thread architecture is the answer, becuase in the end, if the software doesnt support it or take advantage, then its useless. Why would the normal consumer buy a multithreaded cpu if all they do is office tasks, maybe a little gaming, and using the itnernet? It wont speed up things, just allow them to have more windows open at once, but most people dont do 10 things at once. Its a supply and demand thing. When there is a need for smp, then it will come, but atm there is no such need in the mainstream.

The future will bring some rough times as you have said, its inescapable, the physical wall for normal transistor type cpu increases will be reached sooner or later. Thats why advances like carbon nanotubes and other discoveries will form a new architecture on a sub atomic scale.

The point is, evne wiht the end in sight, normal consumers wont be hurt by this for id say easy 15 years, maybe 10-15, but I really think the trickle down will be very slow. And by the time it does affect mainstream, then a new architecture will be ready, becuase you know everyone is aware of this, they arent blind to it, they are preparing
 

darko21

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Re: carbon nanotubes

I read somthing on that stuff, stonger than steel 100 times lighter interesting stuff forsure. are there future plans to use this stuff in cpu designs?

If I glanced at a spilt box of tooth picks on the floor, could I tell you how many are in the pile. Not a chance, But then again I don't have to buy my underware at Kmart.