What's the difference between i5 and i7 processors?

[Dan]

I'm looking at a new laptop, one has:

 

Intel® Core™ i5 Processor 520M(2.40GHz,3MB cache)

 

The other:

 

Intel® Core™ i7 Processor 720QM (1.60Ghz, 6MB cache)

 

but the i7 is more expensive but the speed is lower, why?

[TopherEightyFive]

my guess would be that the i7 is a quad core where as i5 is dual

[Steve]

Topher is right. Not all i5s are dual core, but that one is.

 

i5 520M = 45nm, 512KB L2 cache, 3MB L3 cache, 35 Watt TDP, 2 cores (4 threads with HT), 2.4-2.93 GHz, integrated GPU

 

i7 720QM = 32nm, 1MB L2 cache, 6MB L3 cache, 45 Watt TDP, 4 cores (8 threads with HT), 1.6-2.8 GHz

 

In terms of which to buy, unless you're going to be running apps that can make use of the i7's 4 cores/8 threads, I'd probably go with the i5 for the lower power consumption and integrated GPU. The main difference in benchmarks is when all 4 cores of the i7 are used, then you see a good 50% performance advantage over the i5, but otherwise performance is fairly close, with the i5 slightly outperforming the i7 in cases where just a single/dual core is used, due to the higher clock speed.

[Dan]

Thanks for the info, I'll be using it for Music, Photos and HD video editing. I know Ableton Live supports multicore so maybe the i7 would be best