Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Dual processors. How much Elo difference for the Crafty and Deep Junior?

Author: Robert Hyatt

Date: 06:51:42 12/05/99

Go up one level in this thread


On December 05, 1999 at 03:54:32, O. Veli wrote:

> I would like to learn how much difference a dual-processor would make for a
>chess program? Say a dual 500 Celeron and a dual PIII 450's. I assume it would
>not mean a lot for much of the programs except for the Crafty and the upcoming
>Deep Junior. How much difference could one except for these programs in Elo?
>Thanks for your time.

I would estimate the typical performance improvement (two cpus) at 1.6-1.75
times faster (regardless of estimates you might see that suggest better
numbers).  That is probably about 50 rating points better, since many quote the
70 points per doubling of cpu speed...

I have no idea what kind of speedup Junior gets.  I have lots of good data for
Crafty, that is in the speed-up range given above.  Cray Blitz did better, but
the algorithm was _much_ harder to write and debug, and using a recursive
alpha/beta search I don't see any easy way to implement the DTS algorithm I
used.

Note that there are a few pathological positions that will tear up any parallel
search.  IE it is possible to run _slower_ with 2 cpus than with only one, on
some odd positions.  It is possible to run 10X _slower_ in such cases...  Which
is a headache...



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.