How to compare CPUs?

Question

What are the metrics and their priorities to compare task specific performance of various CPUs?

This is the kind of well-structured question I believe Jeff was referring to in his recent blog post [Q&A is Hard, Let’s Go Shopping!](http://blog.stackoverflow.com/2010/11/qa-is-hard-lets-go-shopping/). While that was oriented toward Super User, system administrators often make purchase decisions and have to balance various trade-offs. It's possible this question could be better worded to include something like "when selecting among server models" to guard against it being migrated. Right now there are four votes to migrate this question to SU, but I don't think it should be. — Dennis Williamson, Nov 23 '10 at 22:09
@Dennis, thank you for advice. I have asked same question for storage solutions for servers. Have a great day. http://serverfault.com/questions/206716/how-to-compare-server-hard-drives — Jeff, Nov 28 '10 at 22:02

score 5 · Accepted Answer · answered Nov 23 '10 at 21:24

I am not sure what you mean with task specific performance, so you will get a slightly generic answer.

There are a lot of different metrics for comparing CPU's, and it depends a lot on what you intend to do with them. The most common meta statistics are:

Performance/price
Performance/watt

And the ever popular weighted index such as

Performance/(price + watt*3 years of electricity)

Performance in turn can be measured in many ways:

MHz (oooh! Marketing!)
Synthetic benchmarks
Memory bandwith (Often the limit in HPC applications)
Application performance for a specific application

You should compare the CPU performance against the intended application. If your application is a virtualization server with 200 virtual hosts you will want a very different CPU from what you need in a mobile phone or in a firewall. Outside the HPC world it's rare that a single test captures most of the performance characteristics you are interested in.

score 2 · Answer 2 · answered Nov 23 '10 at 20:46

2

Usually SpecInt 2006 (http://www.spec.org/cpu2006/CINT2006/) are a good start.

answered Nov 23 '10 at 20:46

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score 0 · Answer 3 · answered Nov 23 '10 at 21:25

One thing you can look at as well is to look at the instruction sets included on the chip. Does the chip support extensions like SSE2, SSE3, SSSE4, SSSE4.1, SSSE4.2 extensions as well? These will effect task specific performance of various CPU's.

http://www.cpuid.com/softwares/cpu-z.html --> tool for checking processor instruction sets.

http://en.wikipedia.org/wiki/SSE4 -> Streaming SIMD Extensions 4

How to compare CPUs?

3 Answers3