# CPU Speed vs. Cores



## FXB

When buying a CPU, Which is best? A CPU with more cores say a quad core or hexa core? OR A fast CPU that runs at say 4ghz or so?


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## Aastii

FXB said:


> When buying a CPU, Which is best? A CPU with more cores say a quad core or hexa core? OR A fast CPU that runs at say 4ghz or so?



I'd take the extra cores any day, because you can overclock it to the same speeds, and also because a quad core @2GHz, will almost always win out against a dual @ 3+GHz (unless it is say an athlon x4 (not athlon II) vs i3)


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## FXB

Aastii said:


> I'd take the extra cores any day, because you can overclock it to the same speeds, and also because a quad core @2GHz, will almost always win out against a dual @ 3+GHz (unless it is say an athlon x4 (not athlon II) vs i3)



from there any preference between AMD and Intel?


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## Geoff

FXB said:


> from there any preference between AMD and Intel?


The Intel i7's are better clock for clock, but are more expensive.


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## Aastii

FXB said:


> from there any preference between AMD and Intel?



depends on budget and function, but generally no, both will perform as well in a given situation as the other. a phenom II 955 or 965 will game as well as an i5 or i7, an x2 or x3 will do as well as an i3, there really isn't anything, other than generally AMD are cheaper than intel, but it comes down to which you would prefer, and asI say, your budget.

I went AMD for 2 reaons:

I didn't have much money
I wanted to play with the processor, and with unlocking cores, it gave me more to do

If I had more money, I'd have gone for an i5 system probably, but with that said, I would have still thought alot about going AMD. Both have their pros and cons



			
				[-0MEGA-];1476498 said:
			
		

> The Intel i7's are better clock for clock, but are more expensive.



In benchmarks, yes, in real world situations, there isn't a noticable difference


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## mtb211

More cores for sure, I was so surprised how fast my I5 was, if your not on a budget then go Intel


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## tlarkin

clock speed is not the end all be all feature of a CPU, and there is a good reason why Intel and AMD really don't go far beyond the 3Ghz realm for their CPUs.  Instead they add more features, more on die cache, more cores, more instruction sets, etc.


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## Dillan500

how about a 4ghz dual core intel i5 vs a 2.1ghz quad phenom?

wouldn't the i5 be faster on non multitasking?
and the phenom be faster with multitasking?

or would i5's Hyper Threading even it out?


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## tlarkin

Dillan500 said:


> how about a 4ghz dual core intel i5 vs a 2.1ghz quad phenom?
> 
> wouldn't the i5 be faster on non multitasking?
> and the phenom be faster with multitasking?
> 
> or would i5's Hyper Threading even it out?



aren't all i5 and i7 processors quad core?


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## mtb211

nah larkin, some i5s are dual.. just have higher speeds...

I think all i7s are 4 or 6


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## salvage-this

Dillan500 said:


> how about a 4ghz dual core intel i5 vs a 2.1ghz quad phenom?
> 
> wouldn't the i5 be faster on non multitasking?
> and the phenom be faster with multitasking?
> 
> or would i5's Hyper Threading even it out?



For single threaded applications, the higher the speed the better it will perform.  (This is throwing out that from what I have seen Intel is a bit better at floating point and other integer computations.)

for multitasking, I would chose the quad core phenom.  If the tasks can be spread out over all four cores then IMO, it should be a bit faster.  As for as I understand hyper threading, I can't seem to find the source but I heard that it only gives you about a 30% increase over your original dual core performance. Since you have 2 physical cores and 2 virtual cores, it should be slower than 4 physical cores.  

I think that you might not see much of a difference unless you are really pushing your processor.


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## StrangleHold

Dillan500 said:


> how about a 4ghz dual core intel i5 vs a 2.1ghz quad phenom?


 
What Phenom Quad at 2.1ghz, are you talking about. If its a Phenom I dont get it. At this point if you go AMD get a Athlon II or Phenom II


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## valtopps

go with intel, get a e8400 and overclock it to 4ghz. they go for $90.00 to 100.00 used.


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## FXB

Where could I find a comparaison chart between AMD and Intel processors?


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## tlarkin

salvage-this said:


> For single threaded applications, the higher the speed the better it will perform.  (This is throwing out that from what I have seen Intel is a bit better at floating point and other integer computations.)



Nope not always, as you still have on die cache, instruction sets, and so forth.  If I were to take a 3.0Ghz P4 with HT, and a Core Duo (not core 2 duo) that was 2.5Ghz, the Core Duo would be a lot faster, still.  Clock speed is not the end all be all.



> for multitasking, I would chose the quad core phenom.  If the tasks can be spread out over all four cores then IMO, it should be a bit faster.  As for as I understand hyper threading, I can't seem to find the source but I heard that it only gives you about a 30% increase over your original dual core performance. Since you have 2 physical cores and 2 virtual cores, it should be slower than 4 physical cores.



True for the most part, but a lot of it also relies on software.  Also, trying to say system A and system B will have a 30% performance difference is really not even close to a real world comparison.



> I think that you might not see much of a difference unless you are really pushing your processor.



This is actually the best thing anyone has posted yet.  It all depends on if you are going to use such features and abilities of your hardware.  If you aren't going to push it to that limit, might as well just go with your cheapest option.


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## spynoodle

FXB said:


> When buying a CPU, Which is best? A CPU with more cores say a quad core or hexa core? OR A fast CPU that runs at say 4ghz or so?


There's a lot more to CPU performance besides clock speed and number of cores.

In general, this can be said about CPU performance:
A multi-core CPU taking advantage of all its cores will be as powerful as its number of cores times a single core of itself, or a single-core version of the processor. For example, a Core2 Quad Q9650, using all four of its cores, should be twice as powerful as a Core2 Duo E8400, both of which run at 3GHz. The Core2 Quad has double the cache and cores as the Core2 Duo. The same goes for a Prescott Pentium 4 at 2.8GHz vs. a Smithfield Pentium D at 2.8GHz. Of course, in that scenario, you also have to count in hyperthreading on the Pentium 4. Also, a processor with double the clock frequency of another processor with the same core design and number of cores should be twice as fast as the slower processor. Therefore, if you had a Cedar Mill Pentium 4 at 5.6GHz, it should be just as fast as its Presler Pentium D equivalent at 2.8GHz.


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## WhiteTree

> Where could I find a comparaison chart between AMD and Intel processors?



Anandtech's Bench is good for arbitrary CPU comparisons. Choose two CPUs to compare in the "CPU Product Benchmarks" section.


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## fastdude

mtb211 said:


> nah larkin, some i5s are dual.. just have higher speeds...
> 
> I think all i7s are 4 or 6




i5-650/660/670/680/661 = dual core
i5-7** = Quad core
i7-8/9** = quad core
i7-970/980X = Hex-core


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## linkin

tlarkin said:


> clock speed is not the end all be all feature of a CPU, and there is a good reason why Intel and AMD really don't go far beyond the 3Ghz realm for their CPUs.  Instead they add more features, more on die cache, more cores, more instruction sets, etc.



You sure? isn't the 965 stock clocked at 3.4ghz? I believe AMD and Intel keep most of their chips around 2.4-2.8ghz as well.

Hopefully bulldozer fixes the other things. It should seeing as it requires a new socket.


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## tlarkin

linkin said:


> You sure? isn't the 965 stock clocked at 3.4ghz? I believe AMD and Intel keep most of their chips around 2.4-2.8ghz as well.
> 
> Hopefully bulldozer fixes the other things. It should seeing as it requires a new socket.



I've never seen stock processors go 4Ghz with maybe a few exceptions of certain systems, but they aren't consumer hardware.  Anything over the 3Ghz barrier tends to generate too much heat for consumer level computers.


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## Hsv_Man

tlarkin said:


> I've never seen stock processors go 4Ghz with maybe a few exceptions of certain systems, but they aren't consumer hardware.  Anything over the 3Ghz barrier tends to generate too much heat for consumer level computers.



Tlarkin is right intel has never to my knowledge had a processor advertised "try our new xx processor over 3.8 ghz of processing power." This just does not happen.


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## Drenlin

^ Actually, the Pentium 4 672 was 3.8GHz... :/


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## maroon1

Dillan500 said:


> how about a 4ghz dual core intel i5 vs a 2.1ghz quad phenom?
> 
> wouldn't the i5 be faster on non multitasking?
> and the phenom be faster with multitasking?
> 
> or would i5's Hyper Threading even it out?



i5 dual core @ 4GHz would be much faster than Phenom X4 2.1GHz in both multitasking and single threaded applications

However the difference in single threaded applications would be much bigger

But I don't think there is a phenom X4 with only 2.1GHz clock speed, anyway

Also, I don't recommend i5 6xx series because you can buy i5 7xx which has 4 real cores, not 2 real cores + 2 virtual cores


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## FXB

Most if not all the i5's are dual core.  All the i7's are quad core.  I don't think any of them are hexa-core.

What's your take on the AMD phenom II X4 955 black edition at 3.2 GHz?


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## Aastii

FXB said:


> Most if not all the i5's are dual core.  All the i7's are quad core.  I don't think any of them are hexa-core.
> 
> What's your take on the AMD phenom II X4 955 black edition at 3.2 GHz?



Most of the i5's are dual core, but advertised at quads because of hyperthreading, making 1 physical core into 2 virtual cores. Any i5's with the name 6xx are dual, those with 7xx are true quad.

All i7's are quad, except for 970 and 980x, which are hex core

The 955 is a very good processor, it will perform as well in games and every day applications than your intel processors will, so for price if you are building a gaming/every day system, then it would be the better option, but if you are using CPU intensive programs, an i7 would probably be better because of better speeds clock for clock and better FP calculations. With the 955 though, make sure it is C3 stepping, not C2, as C3 runs cooler and overclocks a hell of alot better than C2

You can tell if it is C2 or C3 because of the name. Look at the last 4 digits of the product code:

IBOX = C2
MBOX = C3


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## FXB

Aastii said:


> make sure it is C3 stepping, not C2, as C3 runs cooler and overclocks a hell of alot better than C2
> 
> You can tell if it is C2 or C3 because of the name. Look at the last 4 digits of the product code:
> 
> IBOX = C2
> MBOX = C3



What's the whole C2 or C3 thing?


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## FXB

Also what's hyper threading and how is it beneficiary?


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