Is the AMD Fx-8120 a true 8 core?

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willard

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It's like hyperthreading +1. More of the resources are duplicated, resulting in better average performance, but it's still not really an 8 core chip. Combine this with the exceptional low IPC in Bulldozer based chips (it's easily the worst of any processor for the last several years), and hyperthreaded Intel chips at lower clock speeds consistently outperform them in most situations.

Unless you know for a fact you're going to be using predominantly integer based workloads (if you don't know, then you aren't), the Bulldozer chips are not good buys. Get a Phenom II if you want a cheap chip, and an Ivy Bridge if you want to pay more and get more speed for it.

I really don't see a logical place for Bulldozer in the market.
 

maui67

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Bulldozer has what AMD calls "Modules. Each module features two integer cores and a shared floating point core. So the FX-8150 has 4 modules which consist of 8 integer cores, each pair of integer cores shares 1 floating point core.

The problem that 8 core processors have is that there are only a few applications which can utilize that many cores, the same issue that affects the i7 and its multithreading capability.

And contrary to popular belief, Bulldozer is a decent processor. You can't just look at numbers when looking at benchmarks, you also have to pay attention to the test setup. There are a number of things that Bulldozer does better than the Intel cpus and vice versa. Is the Intel i5/i7 faster than the AMD FX cpus? Generally, yes, but only in benchmarks. In most cases you are not going to be able to tell the difference between the two in a real world setting. People like to say that FX sucks at gaming and that the i5/i7 obliterate and wipe the floor with the FX. However, this is not true. The difference is usually a few frames per second. For example, in this review the FX is only a few FPS less than even the Ivy Bridge: http://www.legitreviews.com/article/1914/10/

Also take a look at these links as well:
http://www.techspot.com/review/452-amd-bulldozer-fx-cpus/page8.html

http://www.madshrimps.be/articles/article/1000220/AMD-FX-8150-Bulldozer-CPU-Review/0#axzz1uCYsktim
 

jaguarskx

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It's not a simple answer. Yes, the FX 8120 does have 8 cores, but each of the cores shares resources with another core. Therefore, one core can be waiting while the other core is busy using those shared resources. The FX-8120 has 4 modules each of them contains two cores and the shared resources.

The shared resources includes the prefetching module, decoding units, a floating point unit and the L2 cache. This design approach is better than Hyper Threading because HT only "creates" virtual cores. Simply stated, the virtual cores shares resources with the physical core much like how every two physical cores shares resources in the FX-8120.

The problem with the FX-8120 is that they process less data/instructions per 1MHz than any processor in the Core i3/i5/i7 series. Therefore, an AMD FX series CPU has to be clocked higher in order to perform as well as their competition.

The real answer is a lot more complex than what I have stated, but I think what I've provided should suffice.
 

watters1996

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Okay, so i will be using this new custom build pc for playing games such as the sims 3, flight simulator deluxe, dirt 3 ect. i will also be doing emails and facebook and forums along with some media editing. so should this setup be good? i have little patience so hopefully everything will be near enough instant?
 

madooo12

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it contains two 128-bit FP units which can be combined to form one 256-bit FP unit
 

madooo12

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if 'along with' means multitasking, then BD is much much better than SNB, even sometimes it scales better than SNB-E, 6.66 on cinebench as i remember from amdfx.blogspot.com,

plus BD should give you a better overall experience, according to the AMD blind test
 

watters1996

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Yeah i read that you can overclock the CPU to 4.0ghz and combine the 8 cores into 4, but there isnt much point buying an ''8 core'' just to turn 4 of them off, so there should be a way to overclock all 8.
 

Rockdpm

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Yea i you havn't gotten it yet.. i would get a Sandy Bridge i5/i7. I used Bulldozer for a while and was disappointed. a 560 ti with the FX chip i used was claimed to run BF3 ultra 1080p but i tried it... NO!. tried two GTX 560 ti's for ultra.... still no... tired the Phenom II and can play the campaign on ultra but not Multiplayer... Before i switch i couldnt handle Multi or single player on ultra with 1 or 2 gpu's. I have made up my mind i will get a card with more vram and afterwards i will be getting intel. Piledriver will most likely be another FAIL, so i basically got my 990FX board for nada
 

jaguarskx

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The three most intensive task you listed are Flight Sim X, Dirt 3 and "some media editing". The rest does not really matter. Flight Sim X is very CPU bound. Unfortunately, I have not seen any benchmarks that compares the performance of the FX to a Core i5/i7. Therefore, I can't which CPU will perform better for this particular game.

Dirt 3 is easy, the FX-8150 will loose a Core i5/i7; but not by too much unless you are going to play at low resolution. Since the FX-8120 is slower than the FX-8150 the performance will naturally be less.





Source: http://www.anandtech.com/show/4955/the-bulldozer-review-amd-fx8150-tested/8


"Some media editing"... well the closest would be encoding video using the x264 codec. As you can see below, the Core i5/i7 easily outperforms a FX-8150 in the 1st pass. But it's the 2nd pass that's more important because it takes longer to complete the 2nd pass. The FX-8150 easily beats the Core i5-2500k so you can expect that the FX-8150 will complete the entire encoding process sooner than the i5-2500k. However, thanks to the i7-2600k's Hyper Threading abilities it is slightly quicker than the FX-8150 in the 2nd pass. Therefore, overall the i7-2600k will finish the entire encoding process before the FX-8150. Naturally the FX-8120 will take a little longer to encode video when compared to the FX-8150.





Source: http://www.anandtech.com/show/4955/the-bulldozer-review-amd-fx8150-tested/7
 

4745454b

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it contains two 128-bit FP units which can be combined to form one 256-bit FP unit
And personally I feel the chip is messed up here. My gut says it spends too much time "in 256bit mode" and not enough doing two separate 128bit work. There is also the issue of the reduced front end compared to PhII. The front end is also horribly small.

http://www.anandtech.com/show/4955/the-bulldozer-review-amd-fx8150-tested/2

Notice that as long as you deal with a single core you are fine, but at dual and quad core you are able to decode less often then the old PhII. When looking at quad core rates the old PhII is able to decode 12 instructions to the BDs 8.

As mentioned the answer is kinda. It's sometimes an 8 core and sometimes a quad. But hopefully as that last link showed the ability of quad core CPUs to decode data to work on isn't equal. When looking at quad core rates both the old PhII and the i7 are able to start decoding data a lot faster then the new BD. Core count isn't everything.

 

willard

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Sorry maui67, almost everything you said is extremely deceptive and misleading.
The problem that 8 core processors have is that there are only a few applications which can utilize that many cores, the same issue that affects the i7 and its multithreading capability.
It's the same issue, yes, but because so much of Bulldozer's processing power is tied up in its core count you can't just dismiss the issue. The fact is that Bulldozer is affected much more severely by poor multithreading than Sandy Bridge or Ivy Bridge, which is why it gets absolutely destroyed in single threaded applications. Clock for clock, Bulldozer is the slowest chip on the market. Yes, there's a perfectly good reason that Bulldozer runs slower than it should. Knowing and stating this reason doesn't make the chip any faster, though.

There are a number of things that Bulldozer does better than the Intel cpus and vice versa.
Glossing over the fact that while both have their strengths and weaknesses, SNB/IVB have a lot more strengths and a lot fewer weaknesses than Bulldozer. Basically the only thing Bulldozer actually does really well is highly parallel workloads that involve no floating point calculations. Those workloads are almost nonexistent outside servers (which is funny, because the BD server chips are even farther behind than their desktop chips), which is why the chip fares so poorly in so many benchmarks, and does well in so few.

However, this is not true. The difference is usually a few frames per second. For example, in this review the FX is only a few FPS less than even the Ivy Bridge
You neglect to mention that the reason it's only a few FPS behind is because neither CPU is running at full speed. In reality the Bulldozer chip is running under a higher load, consuming more energy and putting out more heat to perform the same amount of work. When you remove the GPU bottleneck, Bulldozer falls very, very far behind. If your only uses are gaming and web browsing, I can't help but think you're wasting your money buying anything more powerful than a Phenom II. You just don't need the CPU speed.

Using bottlenecked games as an argument in favor of Bulldozer is like saying "Hey, you clearly don't need to spend $200+ on a CPU, so you should obviously buy the least powerful $200 CPU you can find." The conclusion does not follow.

Is the Intel i5/i7 faster than the AMD FX cpus? Generally, yes, but only in benchmarks.
No, Intel is just plain generally faster, not limited to benchmarks. Many of those benchmarks that you dismiss are actual applications that people use every day. They just happen to have highly repeatable results, so they're also great for comparing the relative power of chips.

Also, you seem to have confused benchmarks with synthetics. A benchmark is an incredibly useful way to compare processors, and is literally the only objective way to do so. They've been used for decades and are accepted by the world at large as a fair way to compare performance.

Synthetics (like PCMark), on the other hand, are programs that do not represent actual usage, and instead exist only to apply a predetermined load on a processor. These can show significant differences between largely equal chips due to idiosyncrasies in the way the chips work. This can result in the benches being meaningless, with a chip putting up unusually low or high numbers, or expose design flaws, like Bulldozer's crippled floating point performance.

In most cases you are not going to be able to tell the difference between the two in a real world setting.
If by "most cases" you mean Facebook and video games. In almost anything that can actually make use of the processing power without some other bit of hardware getting in the way, SNB/IVB stomp Bulldozer into the ground. The only time Bulldozer wins? Massively parallel integer exclusive workloads. Also known as server workloads.

You also neglect to mention that in these cases you also can't tell the difference between a Phenom II and a Bulldozer. I don't think it's meaningful in any way to point out that when you're not asking much of your CPU, you don't need the most powerful CPU. File that one under N for "No ***, Sherlock."
 

buzznut

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The easy answer is an 8 core BD performs on par with a quad core. As mentioned, software including operating systems are not optimized to use BD as intended.

But that doesn't matter, what does matter is that it works like a quad core mostly.

In terms of overclocking, BD overclocks a hell of a lot better than Phenom. In fact it overclocks as well as anything from Intel, however that won't give you more performance than the Intel CPU's. Unless you mess with the processor cores, you certainly will be overclocking all "8" cores. Which as I said you should really think of as 4 cores.

That said, most BD owners have noticed a shift since the new year began where the FX8120 does not overclock to the level of the FX 8150. It appears AMD is binning the CPU's differentlly. Now the best one can hope for with the 8120 is about 4.4 Ghz. The 8150 can be consistently overclocked to the 4.7 range, or 4.8 with water cooling and a top o the line mobo. But to me that does not make the 8150 worth $50 more.

 

willard

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Especially considering that for less than an 8150, the 2500k will do 4.7 on stock cooling and frequently 5.0+ on cheap air. Plus the 2500k is substantially faster clock for clock.
 
Both Intel HTT and AMD CMT are basically SMT implementations. Sure, AMD's is a heck of a lot more powerful, but its still SMT. So it comes down to the definition of a "core", which I have yet had anyone define.
 

watters1996

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okay, i already payed and brought this processor with a gigabyte motherboard and 4gb ram, before i ordered it i read all the reviews i could find and they generally were good, so its too late now ive got what ive got. (check my signature thing below)

my old pc was a 2ghz amd sempron 3600+ with 3gb ddr2 ram and a acer f690gvm mobo, so my new pc should be a major improvement yes?

its going to be used for is a bit of youtube, some facebook and emailing, a lot of internet, some gaming such as flight simulator and the sims and my 6th form work (word documents). so it should be good enough for those tasks yes? also i do some light multitasking
 

buzznut

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Sorry, not seeing the sig but +1 what Willard said.
 

noob2222

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I love how people only compare the 8150 on price points vs the 2500k especially when the topic is the 8120. The 8120 can easily do 4.2-4.4 ghz and up to 4.7+ The 8150 is easier to push to 5.0+ ghz
contrary to popular demand for Intel, the 8120 will work just fine and only uses 20 watts more than the Intel solution ... people love to blow the story up, kinda like this fish I caught one time, I swear it was 200 lbs bass. Biggest fish in the world, swallowed a man whole.
 

buzznut

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Exactly. The added cost does not justify the purchase when a better solution can be had for less. I just believe the FX 8120 at 4.4 Ghz will generally be as good as or better than the Phenoms at 3.8-4.0. Considering the 8120 is now as low as $180, its not an awful choice as a gaming CPU, even better as an all purpose computing solution.

Still, in the $200 range I would recommend the i5 2500k as the obviously superior CPU.
 

watters1996

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sorry, it might not of saved, but here

AMD FX-8120 @ 3.6GHz (OC'd)
4GB DDR3 1333MHz Ram (1 stick)
Gigabyte 970A-DS3
Radeon X700 Pro (256MB)
500GB Sata2 HDD
200GB Sata HDD
450watt PSU
Sata DVD-RW Drive
 

willard

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I compared against the 8150 because that's what the post I was responding to was referring to, not that the OP mentioned overclocking at all (which you of course do not take offense to, because it doesn't make the 8150 look bad).

The 8120 can easily do 4.2-4.4 ghz and up to 4.7+ The 8150 is easier to push to 5.0+ ghz
And the 2500k can easily do 4.9-5.1, and remember, the 2500k gets a lot more done on each clock as well. I fail to see any point to be made for Bulldozer here.

contrary to popular demand for Intel, the 8120 will work just fine and only uses 20 watts more than the Intel solution
Nobody is saying the 8120 won't work. In fact, you can find a post of mine earlier in this thread saying that the 8120 is good enough for what the OP was asking about. In debate, this is known as a "straw man" argument, and generally indicates that the debater doesn't have a valid point to make, so they have to misrepresent their opponent's argument in order to make one.

people love to blow the story up, kinda like this fish I caught one time, I swear it was 200 lbs bass. Biggest fish in the world, swallowed a man whole.
Nope, no need to exaggerate anything. Sandy Bridge/Ivy Bridge are simply much better processors than Bulldozer. The only thing Bulldozer has going for it is being marginally cheaper. I'm of the opinion that if you don't need the performance of Sandy Bridge, you also don't need the performance of Bulldozer, and should get a Phenom II instead.

The writing has been on the wall for several months, dude. Accept reality. Bulldozer is not a very good chip.
 
well..at the first lauch of fx processor, i bought fx8120, do hope that i was making a big upgrade from my old 1090T..

three days later...

i sold it to my friend..and put my old 1090T back to the socket..


*true story :D
 

noob2222

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I simply love how people can change 2 sentences into 5 paragraphs. I didn't make separate statements, and I didn't write in bible verses.

Buzzunt said the 8120 can't do over 4.4 ghz .. wrong. I have seen plenty of 8120s running 4.6-4.7 ghz, my own running at 4.7 and had it to 5.0. 4.4 is the low end unless you don't know how to overclock.

My comment about the 8150 is inevitably thats what EVERYONE arguing Intel ops to compare to, always. The 8150 has been, is, and always will be overpriced especially for anyone overclocking. Is that the only arguement that fits Intel is to compare it to the 8150 at stock?

If BD is absolutly soooo horrible, why is it every "overclock" review shows SB clocked significantly higher than BD? http://www.tweaktown.com/reviews/4350/amd_fx_8150_bulldozer_gaming_performance_analysis/index5.html

Shouldn't they desire to show you that at even clocks bd sucks? No, instead they have to show you that SB clocks higher after sifting through the chips for 9 months to find the best OC chip out there, vs 1 day playing with the sample AMD sent. Why is that? Why do NONE of these reviews show equal clocked cpus?

But instead Phenom II is a far superior chip ....



in 3 benchmarks. <-- fish story, its true, PII blows BD out of the water in all cases.
 
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