[RC5] Optimal core question

Décio Luiz Gazzoni Filho decio at revistapcs.com.br
Thu Oct 2 22:41:49 EDT 2003

Hash: SHA1

On Thursday 02 October 2003 22:59, Daniel Quintiliani wrote:
> Hi,
> I see that you guys here usually talk about CPU cores. One of my
> distributed.net computers is a Pentium II 450 running Linux which (using
> the default core) goes at a rate of about 900 something thousand keys/s.
> However, I downclock my CPU due to strange heating problems to 300 MHz
> using a 66 MHz bus speed instead of 100. The rate after the downclocking
> is 600 something thousand keys/s. The program still detects a PII since
> that's what the BIOS reports, but I was wondering if there was a different
> core I could manually select that worked better with PII Celerons. (The
> processor still has the cache features of the Pentium that the Celeron
> doesn't have).

As far as RC5 is concerned, caching and bus speeds are a non-issue. It should 
work as well on your 66-MHz, 128 KB L2 cache Celeron as on the newest 0.13u 
PIIIs with 512 KB L2 cache. As long as the core is the same (the P6 core for 
all of them), it should use the same core and get the same rate per clock.

(This might not be entirely true: I remember reading the PPro had a different 
L1 cache latency, but I might be wrong. This may affect rates of cores 
running on that processor, but I don't think thnat a core coder can do 
anything to counter taht anyway).

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