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Old 2009-09-06, 16:25   #1
mack
 
Sep 2009

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Default Cpu Properties

what CPU properties (multicore, gHz, cache, etc) provide the quickest results?
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Old 2009-09-06, 16:39   #2
CRGreathouse
 
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More, more, and more/same. Output is directly proportional (ceteris paribus) to GHz and #cores, assuming you run one test per core. More cache doesn't hurt, but I don't think it really helps much in this case.
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Old 2009-09-07, 05:48   #3
cheesehead
 
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There's also the speed with which data can be transferred from memory to the registers for performing arithmetic. This memory bus speed is not always proportional to CPU clock speed, and it is often the most-limiting factor for prime95 computation speed.

Sometimes the program "stalls" for a few CPU cycles at a time because the data needed for the next arithmetic step has not yet arrived from memory (even the L1 cache!) when the CPU is ready to start doing the arithmetic. There was a lot of programming effort devoted to minimizing these "stall" times. Not all could be eliminated.

Last fiddled with by cheesehead on 2009-09-07 at 05:49
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