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Subject: Re: Since the CPU is what really count for Chess !

Author: Robert Hyatt

Date: 07:12:56 03/18/03

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On March 18, 2003 at 00:24:01, Aaron Gordon wrote:

>On March 18, 2003 at 00:01:44, Robert Hyatt wrote:
>
>>On March 17, 2003 at 22:59:30, Aaron Gordon wrote:
>>
>>>On March 17, 2003 at 18:47:27, Eugene Nalimov wrote:
>>>
>>>>I just run the experiment. I used 2 otherwise identical 64-bit systems, one with
>>>>3Mb of L3 cache, other with 1.5Mb. Machine with bigger cache run Crafty's
>>>>"bench" comman 12% faster (1 CPU).
>>>>
>>>>That means that
>>>>(1) Crafty's working set don't fit into 1.5Mb,
>>>>(2) For systems with cache 1.5Mb or less (i.e. for almost all x86 systems) for
>>>>Crafty memory speed matter.
>>>>
>>>>Thanks,
>>>>Eugene
>>>
>>>Those types of systems aren't what people normally use. Most people here have a
>>>Pentium 3, Athlon, Pentium 4, etc. Here is something I found with Crafty.
>>>
>>>Using the Nforce2 chipset I'm able to run the ram at speeds from 50% up to 200%
>>>(100% being synchronous) of the fsb speed. I tested 200MHz FSB (400DDR) with
>>>200MHz memory (400DDR) and 200fsb with 100MHz memory (200DDR).
>>>The difference between ~1.6gb/s memory and ~3.2gb/s memory with craftys 'bench'
>>>command was 0.14%. Yes, about one seventh of one percent.
>>
>>That might well suggest _another_ bottleneck in that particular machine....
>
>Another bottleneck? What was the original one?


The original one was assumed to be bus speed.  That's where I entered the
discussion.  But bus speed is not the _only_ issue that can cause problems
here.

Lack of interleaving is another.



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