Laptop CPU questions

[esperasoppa]

Could anyone help explain to me the main differences between the i5 and i7 series for laptops?

I just checked the Intel website, and the only difference I can see between is the cache size. What difference does 3MB of cache makes?

Also, why would they make some i7 dual core, wouldn't it be simpler to have all i5s dual core (which they all are) and all i7s quad core? This would make it so much easier to choose processors, unless I'm missing something?

Someone please enlighten me on this.

[BigPhatPaulie]

Which laptop? Some of the I7 duals for laptops will turbo much higher than their I5 counterpart. However you will really only ever see I7 duals in ultrabooks. In normal laptops most(if not all) I5's are quads and I7's are quads with hyperthreading

[JJThomp]

No for laptops i3 are 2cores/2threads, i5 are 2c/4t, and i7 are 4c/4t. Some i7 are duals for 4threads but they usually are clocked really high.

[Bond007]

Originally Posted by JJThomp

No for laptops i3 are 2cores/2threads, i5 are 2c/4t, and i7 are 4c/4t. Some i7 are duals for 4threads but they usually are clocked really high.

Not true. In mobile all i3/i5/i7 have hyperthreading.

i5 adda turboboost over i3. lower end i7 are slightly faster versions of i5 with an extra mb of cache. And the higher end i7 are 4 core 8 thread. Here is a link to a summary chart from wikipedia to see it all.

Sandy Bridge - Wikipedia, the free encyclopedia

[dandelioneater]

Wikipedia (as posted above) should have lists/specs of all the intel mobile cpus. I always refer there to make sure that I know what I am getting so that I can judge whether or not the price is reasonable on a laptop.

[frontier204]

As you are alluding to right there, Intel has one of the most confusing scheme for model numbers. I've just learned to go straight to Intel's web site to look at the model details and not ask
There's also little differences here and there like what kind of virtualization support you get, and if the CPU supports AES-NI (hardware accelerated encryption).

I couldn't find benchmarks for what kind of difference the cache makes for a mobile Sandy Bridge, but with other CPUs (the older Phenom X4 vs Athlon X4), cache made some differences in gaming. If you are comparing a dual core i5 and i7 however, I'm willing to assume the performance difference will come from the higher clock speeds rather than the cache, since 3MB is plenty for a dual core in most loads.

[esperasoppa]

All mobile Intel iCPU have hyper-threading if you are unsure about that.

@frontier: Thanks, I think your explanation is right on it.