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Subject: Re: CSTal-2 vs Crafty 16.15 game 8

Author: Robert Hyatt

Date: 10:47:01 09/13/99

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On September 13, 1999 at 12:39:11, Thorsten Czub wrote:

>On September 13, 1999 at 08:37:05, blass uri wrote:
>
>>On September 13, 1999 at 05:51:40, Thorsten Czub wrote:
>>
>><snipped>
>>>this is a shallow evaluation. In my games against Hiarcs7.32 CSTal
>>>gets 50%-.
>>
>>Maybe Hiarcs does not like your hardware.
>>I know that in one of your games Hiarcs7.32 did a stupid blunder that my
>>hiarcs7.32 could not reproduce and hiarcs can see from the first ply that it is
>>a blunder.
>>
>>I know that mark young claims that he did not find strange blunders in games
>>when Hiarcs used the pentium.
>
>my amd k6-400 gets normal benchmarks for hiarcs.
>
>
>>Uri


I am hardly an Intel bigot, as I happen to love alphas. :)  However, here is
one horror story about a non-overclocked AMD.

A student came in to my office about 2 years ago or so wanting to buy a good
computer that would have enough horsepower for his Ph.D. research in data
mining.  I had heard good things about AMD and he ended up buying a K6.  He
seemed happy at first, but came by one day with a problem where his program
was crashing unexpectedly.  I gave him some suggestions on debugging, but none
helped.  It ran _so_ long to crash, he asked if he could also use a couple of
the machines in one of the labs here so he could do different debug tests at the
same time, and I said "sure."  He dropped this program into his AMD and two
Intel boxes, and suddenly they were running to completion on the intel boxes,
but still crashing on his AMD.  He tried the same data exactly, and it would
crash on his AMD, but run on the Intel boxes.  After a lot of searching, it
turned out that AMD had released a bad batch of cpus with a known math error
in them (does sound like the infamous intel floating point bug, to be sure) and
he had gotten one.  After 3 months of work, he found that _all_ of his testing
had been for nothing...  a big waste of time...  as his CPU was bad.

Others here have reported bogus results with crafty, and upon further
examination I have found that they are usually running on an AMD that is
overclocked.  That seems to work for a while, but as the cpu heats up, it
starts producing some sort of funny math error that will screw things up in
ways that are totally unreproducible.

For those reasons, I stay away from them myself, and will continue to do so
until I see 'saner' behavior from the processors.  Finding that sort of problem
is nearly impossible without hardware logic analyzers and so forth, and at these
clock speeds, such analyzers are not cheap.

YMMV of course...



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