Dual-core vs quad-core

[apisorder]

Hi guys,

I think this may be a dumb question, so please excuse my lack of knowledge.
(Originally I was going to post this in the laptop section but since it's mainly about CPU's, I thought this is a more fitting place.)

Is quad-core necessarily better (in terms of performance) than a dual-core in a laptop?

To my understanding, most apps do not yet utilize anything more than 2 cores, so why buy a 4 core machine sporting an i7 processor, as opposed to a daul-core i5?

Another confusion I had is the low clock speed of quad-core i-series processors. Yes, they can overclock (or run in turbo mode rather) to a much higher clock, but wouldn't the initial lower clock gives a lower overall system performance? (compared an i7 processor at 1.7 Ghz as opposed to an i5 processor at 2.5 Ghz)

The last confusion I had is about ultrabooks. If the reason to have an i7 processor in a laptop is because it offers 4 cores (instead of 2 cores) and its relatively larger cache, why settle for an ultrabook which currently only sports a dual-core i7 processor? How is it that Apple is able to squeeze a regular quad-core i7 processor in an ultrabook that PC can't, or won't?

Thanks,


Apisorder

 

[amuffin]

Depends on the application at hand!


The ultrabook i7's are still dual core, if i remember correctly they are just clocked higher than the i5's.

 

[apisorder]

Hi amuffin,

Then what's the point of buying an i7 in this case?

(I think for most apps the SSD will be more of a performance factor than anything else, and while 4G is plenty for most uses, the dedicated VGA on ultrabook is simply not great for games/scientific computation, which would benefit from a higher cpu clock, right?)


Thanks,

Apisorder

 

[amuffin]

There really is no point!

I'm not sure if you're familiar with power supplies, but it's like spending the extra money for a fully-modular power supply when you HAVE to use the 24Pin ATX and 8 pin CPU connectors.

 

[2260121]

1st- the need of 2 or 4 core depends on what you want to do with it, not how many apps use 2+ core. So tell us what you will do/do with your laptop and we'll try to help you do the best choice.

2nd- if laptop's procesors are sow low clocked is (imo) because power consumption. You juste have one battery to power the whole thing so if all laptops had fx 8150 @ 4.5 Ghz I don't think the battery could power the rest of the components. Another major issue with laptops is the heat. You can't put an enormous 8 heatpipes heatsink or a watercooling system in a laptop! so they have to clock them lower and btw i dont think you can overclock a mobile processor or if you can, i wouldn't try.

3rd- I hope your not buying from apple. There is so many other great laptops on the market and the only one you found is the overpriced stuff from apple? seriously, you should look somewhere else, you would get so much more for your money but maybe not quality i have to agree.

 

[raytseng]

if you go down this path, what's the point in getting a new computer.

Your computer from 5years ago surfed the web and did everything pretty much the same as you did now.

If it's slow, i argue that it's your harddrive or windows that's all full of viruses. (Do a clean wipe and it should be pretty speedy)

 

[apisorder]

I see.

Thank you, amuffin 🙂


Apisorder

 

[apisorder]

Hi raytseng,

My rationale for getting a new computer is to realize performance and efficiency gains from a new architecture, hence prolonging battery life. Not all of us have room for a battery slice in our already stuffed bag, especially consider the number of textbooks we have to carry ah?

While I agree a clean install of Windows basically cleans up the cluttered hard drive space or Windows registry, this is not always the main factor that contributes to the slowness of the system.

For example, newer SSD, aside with its reliability issues (some new ones have driver/firmware update problems), really reduce system boot time and app load time. So while I agree a 5-year old system can still perform most daily tasks just fine, newer architectures, aside from Intel's purposes to make a profit, do tend to make things faster/more efficient.

I run Adobe CS6 Master Collection on my 2-year old laptop, and while app loading time is quite long, once it is finished loading, they run quite smoothly (they because I run two apps concurrently, Photoshop & Premiere Pro).

I guess I am simply asking if upgrading to a laptop with 4-core, bascially from 2-core i5 to 4-core i7 will really help system performance since I got enough ram (just 8G, but it's enough I find) and a fairly reasonably fast HDD (7200 RPM).

Thanks,

Apisorder

 

[amuffin]

Just look for a laptop with an i7 and dedicated graphics! Adobe CS6 takes great advantage of GPU Acceleration!

 

[apisorder]

Hi 2260121,

For 1, I currently run Adobe CS6 Photoshop & Premiere Pro.
But I think for the Adobe apps, faster CPU is more important, not the # of cores, since they don't utilize more than a dual core (Photoshop could be an exception, however, as I read it somewhere.)

For 2, while I knew a lower clock is due to power consumption requirements, I was wondering if a 4-core system with a lower initial clock would result in an overall system performance than a 2-core system with a higher initial clock, even though the 4-core can turbo higher than the dual-core?

For 3, do you know this for a fact? I know from friends that Dell's Alienware offers quality hardware at a premium, just as Apple does. I mean, they are both expensive, but being expensive doesn't necessarily mean they are not good products right? With that said, Apple is indeed expensive, especially MBP.


Thanks,

Apisorder

 

[raytseng]

if the work and tasks that you do are not pausing or waiting on CPU, then your i7 is not the bottleneck, so yes, you are right in that case, i5 is the way to go to save money since computer is already fast enough.

As far as prolonging battery life, the fastest processor will actually be the best for that since Intel Speedstep comes into play (but will hurt your wallet the most).

At idle, both types of cpus will clockdown and expend about the same power. Unless for some crazy reason you disabled speedstep.

But Given a specific task, the faster processor will finish it faster. And typically the way the math and static power overhead works out, it will consume less total watts-hours (or at least the same).


Look at the power consumption chart for idle, they are the same

http://www.notebookcheck.net/In-Review-Intel-Ivy-Bridge-Dual-Core-CPUs.75342.0.html

They have increases in Watts for the load tests, but
the increases in the i7 tests fail to take into account that the job probably finishes faster, so total power consumption (watt-hours) for the task will be same or less.

People who have calculated watt-hours for a task, do show the faster processors end up being more efficient and take less electrons to do the job.

Or if you do a rough calculation, for example, the i7Q maybe double the speed in Prime, but doesn't take twice as many watts, so calculations/watt is more efficient.

 

[apisorder]

Hi amuffin,

Since GPU acceleration is so important, do I need to get a 4-core over a 2-core, if they are both i7? I heard that only Photoshop can utilize the full 4-core and the others only 2-core.

Why i7 then? If the VGA is good (fast enough), wouldn't it an i5 be just fine?


Which one matters more in this case, CPU speed or # of CPU's?


Thanks,

Apisorder

 

[amuffin]

4 Cores and 8 Threads that the i7 has. Adobe programs can take great advantage of this, especially Premiere pro

 

[apisorder]

Hi raytseng,


Given what you said, a dual-core i7 will not necessarily be more energy efficient than a quad-core counterpart right? (since the quad-core will consume twice as much power when they are idle but the if the apss can utilize quad-core, it may finish sooner) [ although generally it would since just by "sitting" there, a 4-core will consume about twice as much power as its 2-core version. ]

Besides getting the fastest CPU and a SSD, is there another way I can save power when on the go? My current laptop only lasts 3 to 4 hours.


Thanks,

Apisorder

 

[apisorder]

I see. I totally forgot about the hyper-threading thing.


I was wondering, amuffin, does the app need to be able to utilize 4-core to realize the 8 thread benefit as opposed to the 4-thread benefit a 2-core offers?

(So I guess Premiere Pro can utilize 4 core, just as Photoshop does?)


Thanks,


Apisorder

 

[raytseng]

no, at idle, both dual and quad use same power (see previous link). Intel Speedstep is very efficient.


At speed, quad core will use more watts than dual. But will do even more calculations. (I've edited previous post for example, or you can crunch the numbers yourself from the article to get calculations/watt).


So within the same architecture, the highest end processor will be the most battery efficient (but also the most expensive).

 

[Smeg45]

Bottom line, more cores is always better. More resources are there on tap if necessary. If programs are well threaded those 4 cores will be used. If you open up a stack of programs, Windows will shuffle them around the cores/threads as required, and yes, more cores means Windows can work more efficiently. Generally speaking. Personally, I would only buy a laptop or build a PC with a quad, and a real quad, not counting Hyperthreading.

 

[2260121]

Personally, I would only buy a laptop or build a PC with a quad, and a real quad, not counting Hyperthreading.

What, are you saying that my i3 is not a real 4 core?

 

[kristjan_i]

There really is no point!

I'm not sure if you're familiar with power supplies, but it's like spending the extra money for a fully-modular power supply when you HAVE to use the 24Pin ATX and 8 pin CPU connectors.

I'm using C2Q Q6700 , 4-pin cpu header. Power supply's not the case, in desktops, as ihave a cheapo 500watt Chieftec powering cpu, vga and rest of my components.


Coming back to laptops, the power cosumption is not of an big issue aswell, for new technoligies save huge amounts of power.
Heat output is a bigger concern.
A lot of vendors overbuild their laptops, in a manner, that the coolers hardly cool off the quad-core cpu's.

 

[apisorder]

Hi 2260121,

I think generalize from the comments above, the number of cores is the number of physical processors, _not_ the number of processors Windows views, i.e. a dual-core i5 processor has 2 physical CPU's, but Windows 7 views it as having _4_ processors, hence capable of handling 4 threads/processors concurrently.

So if your computer has 2 physical cores, then it's a dual core, which with hyperthreading will be seen by the OS as 4 core/4 threads.

So if your computer has 4 physical cores, then it's a quad core, which with hyperthreading will be seen by the OS as 8 core/8 threads.

I think with AMD however, the story is different.


Hope this helps,

Apisorder

 

[2260121]

Hi 2260121,

I think generalize from the comments above, the number of cores is the number of physical processors, _not_ the number of processors Windows views, i.e. a dual-core i5 processor has 2 physical CPU's, but Windows 7 views it as having _4_ processors, hence capable of handling 4 threads/processors concurrently.

So if your computer has 2 physical cores, then it's a dual core, which with hyperthreading will be seen by the OS as 4 core/4 threads.

So if your computer has 4 physical cores, then it's a quad core, which with hyperthreading will be seen by the OS as 8 core/8 threads.

I think with AMD however, the story is different.


Hope this helps,

Apisorder

I was just kidding when i said that. and btw, amd do not have the hyperthreading feature.

 

[apisorder]

Hi raytseng,


I have a question regarding your comment, "So within the same architecture, the highest end processor will be the most battery efficient (but also the most expensive)."

Does this apply to clock speed or number of cores, and if both, which one takes precedence?

Just out of curiosity, which one would you consider buying, if the hardware config is compatible, Apple or Alienware? Why?

Honestly I really wonder, if I would realize much performance gain by upgrading from a dual-core i5 to a quad-core i7 and from a 7200RPM HDD to a SSD, since my system runs quite fast already (I just don't do that much stuff on it, but I am looking to replace it because my parent wants me laptop so I am looking for a replacement.) Would it? (Would Premeire Pro be the only app where I can realize the difference, according to what you said?)



Thanks,

Apisorder

 

[Idonno]

How is it that Apple is able to squeeze a regular quad-core i7 processor in an ultrabook that PC can't, or won't?

I know that Asus, Sony and lenovo all have quad-core i7 processor options and I'm sure there are more. If it took PC a little longer to adopt a quad in an ultrabook it's most likely because they didn't want to have all the overheating issues that apple is so notorious for and they wanted to find a proper solution to the heat issue first.

 

[apisorder]

Hi Idonno,


This is really going to sound dumb now, but why buy an ultrabook, one that costs more and offers less performance, if not for its lighter weight?


Thanks,

Apisorder

 

[Idonno]

Hi Idonno,


This is really going to sound dumb now, but why buy an ultrabook, one that costs more and offers less performance, if not for its lighter weight?


Thanks,

Apisorder

I personally can see the cool factor but, I wouldn't buy one when you can buy a slightly thicker notebook with better cooling, an optical drive, and many times notebooks have better connectivity. The extra few ounces in weight won't hurt anyone and are well worth the benefits. Of course that's just me.

If your interested in Notebooks Asus has a great line. You should check out their site.