How different about i5/2.4Ghz VS i7/2.66Ghz?

[Yae]

but I think they similar other than Ghz...

They are Dual-core and have Turbo Boost & Hyper-Threading.

 

[Bibble]

Other than the higher i7 clock speed, the main difference is the hyper-threading.

On an i5, the computer actually SEEs 2 cores that it can give processes to, on an i7, each core has 2 virtual cores, so that threaded applications run better.

Basically depends on what you'll be doing with it.

 

[fewture]

I was under impression that both i5 and i7 have hyper threading:

http://www.intel.com/products/processor/corei5/mobile/index.htm

See this ongoing discussion for differences between i5 and i7

https://forums.macrumors.com/threads/896205/