Which Is More Important? Cache or Clock Speed?

godbrother

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Hi, I just found an old Pentium 4 CPU laying around. I never knew I had it, so I tested and it seems to work. The pentium I found is a 3.6Ghz with a 1MB cache, the one I'm useing right now is a 3.2Ghz with a 2MB cache.

Which is better... In this case the 3.6Ghz one... correct?
 
Pentium 4 560 vs Pentium 4 640?
Probably 560 most of the time. But for some usages the larger cache of the 3.2Ghz could influence performance more than the 10% higher speed of the 3.6Ghz CPU.

An example of a E7200 CPU running with 6MB and 3MB cache - showing the different performance values due to cache size:
t2.png

You can see the size of the cache affects programs differently.

I'd expect there might similar variations when you're talking 1MB and 2MB cache.
 

jamesgoddard

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The 3.6 will win at a slim margin - but it will be hotter and use more power.

What stepping is the 641, as the D0 stepping are known to overclock like banshees... I get my 631 to 5GHz stable.
 

blackhawk1928

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Both are utilized for different tasks and both are quite important. It all depends on the software that is being run and/or type of tasks to determine which is one is more important or affects performance more.
 
In general terms, doubling clock speed always gives you almost double the performance, while doubling the cache size does not. Cache is subject to the effect of diminishing returns, but clock speed is not - the performance gain of faster clock speeds is only affected when other components in the system become a bottleneck.
 

joefriday

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Who said anything about the 3.2GHz 2MB L2 cache P4 being a Cedar Mill? It could just be a Prescott-2MB (aka 640). Regardless, the 640 should have at least a rudimentary speed step to decrease power consumption while idle, something the 560 will not.
 

jamesgoddard

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in his sig.... 'CPU: Pentium 4 641 - 3.2Ghz - Hyper Threading - 2MB Cache - 800Mhz FSB - 65nm'