Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: RAM , Hash tbl. and processor speed

Author: Aaron Gordon

Date: 14:20:02 03/27/03

Go up one level in this thread


The two main things you want to do is get a processor that is as fast as
possible and with longer time controls use a hash table that is as big as
possible. With 512mb try not to go above 384mb hash, any more and it'll
definitely swap. 320mb is pretty safe to use. With 256mb ram 160mb hash is
probably going to be your max.

As far as speed goes.. if you use a very large hash table you can generally
(depending on the chess engine) expect to see a 2-10% increase in nodes per
second by doubling your ram speed (going from SDR to DDR for example). If you
use smaller hash tables (less than 32mb or so) you'll see no measurable
difference. If you use 32mb hash vs 320mb hash w/ 512mb ram you'll generally see
a slight drop in nodes per second. This is fine, though, because in long time
controls a larger hash is much, much better.

So far I have noticed with Fritz 5.32 set to 255mb hash gets filled entirely in
about 1 minute at 2.5 million nodes/second on my AthlonXP 2.5GHz.
On FICS I use the computer account "LittleGoliath". For lightning games I use
192mb hash, for short blitz games (3 0 to 4 1) I use 256mb hash, for blitz over
5 1 I use 320mb hash and for standard games I use 384mb hash.

Since your P4-1.8GHz is about the speed of an Athlon 1.2GHz it'd be wise to use
about half of the hash I'm using except for long time controls. So, for your
P4-1.8.. 96mb hash for lightning, 128mb for short blitz, 160mb for longer blitz
and 384mb (or 320mb to ensure no swapping happens) for long time controls would
probably be best. Just uset these hash sizes to start out with. You could get
better results by experimenting with various sizes.. I wouldn't go below those
settings much though.



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.