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I want to estimate how a certain piece of code will perform on different Intel Westmere processors. The various processors all support the same QPI and memory speed, and they all have the same cache sizes; the only difference is the CPU core clock speed (2.66GHz vs. 2.93GHz etc.)
I already have one such processor running with a very fast CPU core clock. I would like to estimate the performance of the others without having to purchase them first.
Using cpufreq-set
on Linux (acpi-cpufreq driver), I can set my core clock speed to a variety of slower values. My question is simply this: Does setting the core clock speed in this way change anything other than the core clock speed? That is, does it precisely simulate a slower CPU, or does it also slow down the front side bus or change the cache size or whatever?
Please provide a reference for your answer. Thank you!
"Processor frequency" is a little vague. There are several clocks flying around inside the processor, the most important being the "Front Side Bus" and the "core". Thank you for your reply, but I already read the Wiki page and I do not believe it answers my question. – Nemo – 2011-09-01T00:46:05.380
1The FSB isnt determined by the processor, its determined by the Northbridge chipset on the motherboard. – Keltari – 2011-09-01T00:57:02.593
1@Nemo: "Processor Frequency" isn't vague at all. The motherboard != processor. Memory != processor. – surfasb – 2011-09-01T03:26:20.647