Whats the difference? i3, i5, i7

[kevinbreault39]

Ive noticed that some of the i5 processors can be up to 3.2ghz, where my i7 920 is only at 2.66. Is the i5 better than mine?
I have only been looking at the speed of the processor when buying them, im guessing there is something else to be looking for?

 

[foothead]

Its a different achitecture, and doesn't have Hyperthreading support. The only time you can fairly use clock speeds to compare CPUs is if they are within the same family, and have the same architecture. Example, for non gaming activities, i7 920 @ 2.66 GHz would need a Phenom II @ ~4.5 GHz to keep up with it. (I drew those numbers from the air, but they would be about right) For gaming, Phenom II would own it though. It all depends.

I would say your 920 beats the i5 @ 3.2 GHz pretty handily, especially because you have triple channel DDR3.

 

[nbrikha]

Ive noticed that some of the i5 processors can be up to 3.2ghz, where my i7 920 is only at 2.66. Is the i5 better than mine?
I have only been looking at the speed of the processor when buying them, im guessing there is something else to be looking for?

i5 are quad cores with no hyperthreading. Think of the CPU as a waterplant. And each core is a turbine pushing water out to a pipe, the threads. Those cores are bottlenecked by how big the pipes that direct the water are. Now the i5 has four cores and four threads. The i7 has four cores and 8 threads, meaning theoretically 8 cores. Also something called turbo boost, which can temporarily disable two of the cores and make the other two much faster, at times 3.2 ghz. That's a basic metaphor of cores and threads and cpus. Help it doesn't leave you more confused.

 

[foothead]

^ Good explanation. The only thing I feel needs to be changed is the 'theoretically 8 cores'

There are still four cores, even in theory. You just have eight virtual cores.

Each core supports two threads, acting as two cores.

 

[Mutant Corn]

Its a different achitecture, and doesn't have Hyperthreading support. The only time you can fairly use clock speeds to compare CPUs is if they are within the same family, and have the same architecture. Example, for non gaming activities, i7 920 @ 2.66 GHz would need a Phenom II @ ~4.5 GHz to keep up with it. (I drew those numbers from the air, but they would be about right) For gaming, Phenom II would own it though. It all depends.

I would say your 920 beats the i5 @ 3.2 GHz pretty handily, especially because you have triple channel DDR3.

True for the most part, but I still fail to see how a PII beats an i7 in gaming. If the PII shows up wit similar scores in a bench, it's almost always because it's GPU limited.

 

[foothead]

True for the most part, but I still fail to see how a PII beats an i7 in gaming. If the PII shows up wit similar scores in a bench, it's almost always because it's GPU limited.

It wins when AA and high resolutions are thrown in. This puts more of the stress on the GPU than the CPU. You need a very good GPU or a high powered crossfire setup for this to actually happen before hitting the GPU's limit.

 

[nbrikha]

You just have eight virtual cores.
Each core supports two threads, acting as two cores.

I would've said virtually but for some reason I thought OP wouldn't get the jist of virtual. In retrospect I should've just said virtually.

 

[Mutant Corn]

So essentially the naming scheme for the nehalem CPU's is like this:

i7 = 8 threads, turbo boost
i5 = 4 threads, turbo boost
i3 = 4 threads, no turbo boost
Pentium/Celeron* = 2 threads, no turbo boost

*not counting that funky socket 1366 celeron

It wins when AA and high resolutions are thrown in. This puts more of the stress on the GPU than the CPU. You need a very good GPU or a high powered crossfire setup for this to actually happen before hitting the GPU's limit.

 

[foothead]

^ No AA, No AF.

Like I said, it pulls ahead when there are high resolutions, AA, and AF, in intensive games. And you need a really powerful GPU for this to happen before the GPU bottleneck.

Don't forget the i7 980x with 6 cores, 12 threads.

 

[Cabbs]

http://www.tomshardware.com/reviews/overclock-phenom-ii,2119-8.html

Both are overclocked, i7@3.8 Ghz vs Phenom II at 3.64 Ghz. Should give a good idea of performance at similar clock speeds. Notice how the i7 is faster almost every time except for Crysis, where the Phenom II is slightly ahead.