Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I'm shopping for a new laptop from Dell (going to install Ubuntu on it) and I'm currently trying to sort out which processor I want.

Based purely on the clock speed, it would seem that the core i5 is better than the core i7.

The Intel® Core™ i5-430M has a 2.26GHz clock speed, while the Intel® Core™ i7-720QM Quad Core Processor only has a 1.6GHz clock speed. Would this not indicate that the i5 is faster than the i7?

share|improve this question
    
The difference between i5 and i7 is mostly in integrated graphics isn't it? –  Ivo Flipse Mar 25 '10 at 21:26
add comment

4 Answers

No, the Megahertz Myth shows how clock-speed comparisons only work within the same range of processors - beyond that, there are too many other changable variables. The i5 is the "budget" version in the i* range, so if you really, really need the extra power (And, indeed, extra power draw) go for the i7, not the i5. (More cores on an i7, and I don't believe the i5s do turbo boost, which overclocks one core while downclocking the rest, for single-threaded CPU hungry applications)

share|improve this answer
    
@Phoshi, I think @Kirk Broadhurst has a point about the i3 being the budget core of the line... –  studiohack Mar 25 '10 at 21:59
    
@studiohack23: Oh. Well, I completely missed that being released! Thanks for the update. –  Phoshi Mar 26 '10 at 15:03
add comment

The i3 is the budget version in the new range. The i5 is the mid-range option, and the i7 is the high performance line. Therefore I'd expect midrange performance, but from a fairly new line the midrange performance is expected to be quite good.

When trying to compare processors I normally look at http://www.cpubenchmark.net/ - it nicely packs everything into one index which can be compared. Certain architectures (and therefore certain product lines and models) suit certain applications more than others, but generally a higher number means more power and can be compared in a fairly linear manner.

share|improve this answer
add comment

I really like the CPU benchmarks at Passmark.Com

They show a nice rating of CPUs so that you can compare between CPUs or Video Cards and get a good idea of the relative performance of the chips. This allows you to decide if the extra cost is worth the incremental performance.

share|improve this answer
add comment

Intel's newer chips use a lower base frequency that is then automatically increased using Turbo Boost when only one or two of the cores are being used. This comparison shows that the i7-720QM is faster with a Max Turbo Frequency of 2.8 GHz vs 2.533 GHz. Not to mention it can run twice as many threads and has VT-D and Trusted Execution capabilities. The main benefit for the i5 would be a lower power envelope (longer battery) and an integrated graphics controller (higher graphics memory bandwidth).

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.