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Subject: Re: here my guess...

Author: Robert Hyatt

Date: 17:50:53 08/11/05

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On August 11, 2005 at 15:30:25, Peter Berger wrote:

>On August 11, 2005 at 13:53:37, Robert Hyatt wrote:
>
>>That will be a miracle.  A single opteron CPU (single core) is 2x as fast as a
>>3.0ghz pentium.  I, at least, will be running on 8 of 'em.  That is a tough
>>disadvantage to overcome...
>
>The question is how much this amounts to. Let's call the hardware 16 times
>faster, how much faster will Crafty be when running on both of them? So far I
>have only seen NPS comparisons reported but no time-to-ply comparisons. Do you
>think you will get more than 10 times faster performance out of the faster
>hardware?
>
>With 10 times faster you'd only have sth like maybe 200-250 Elo difference (
>simplified) by hardware.


I ran some tests last night.  The data is "rough" as I'd like to re-run the same
25 CB/mchesspro positions I used last year at least 16 times.  The rough data
was comparing the one cpu 875 (one physical process) to 8 cpus (8 physical
processes).  The average speedup was around 6.0, after yesterday's marathon
tuning activities.  So I suppose that factors into about 12X faster than a
3.0ghz xeon, if the math holds.

Again, note that that 6.0 number is from one run of a batch of positions, just
to get a feeel for what the tuning I had done was doing to the search.  It is
actually possible to do a bit better in middlegame positions, by different
tuning, but that tends to impact endgame searches.  The current tuning is set to
achieve a reasonable balance on all positions...

Sorry I don't have the kind of data I gave to Martin last year.  But I will
certainly rerun that same test again for 1, 2, 4 and 8 processors as soon as the
WCCC is over, then I can supply some real data over multiple runs...




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