Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: How much hash for Blitz?

Author: Robert Hyatt

Date: 09:08:23 04/28/03

Go up one level in this thread


On April 27, 2003 at 16:35:20, Jorge Pichard wrote:

>On April 27, 2003 at 11:01:18, Robert Hyatt wrote:
>
>>On April 27, 2003 at 05:34:04, Jorge Pichard wrote:
>>
>>>On April 26, 2003 at 22:49:57, enrico carrisco wrote:
>>>
>>>>On April 26, 2003 at 14:16:14, Jorge Pichard wrote:
>>>>
>>>>>On April 26, 2003 at 12:27:28, Anson T J wrote:
>>>>>
>>>>>>I'm going to run a few games of blitz @ the time control 3mins + 2sec (inc)
>>>>>>
>>>>>>On a dual AMD XP2400+ is 128 MB hash sufficient for Deep Fritz 7?
>>>>>
>>>>>For Blitz of less than 30 Minutes 64 MB hash would be more efficient.
>>>>
>>>>Not necessarily true for these faster systems.  Has someone tested performance
>>>>regarding hash size with 2GHz+ machines?
>>>>
>>>>In the case of HIARCS, more hash does not inhibit performance.
>>>>
>>>>-elc.
>>>
>>>I have three computers a Celeron 450 Mhz, an Athlon 1200 GHz and a XP2800+ with
>>>512 MB, but for Blitz of less than 30 Minutes, 64 MB hash run faster than using
>>>128 MB.
>>>
>>>Jorge
>>
>>
>>What metric are you using to measure speed?
>>
>>NPS or time to depth?
>>
>>NPS is not what you want to maximize.
>
>
>I measure depth within certain seconds, for instance in 10 seconds what depth
>does it reach with 64 MB versus using 128 MB.
>
>Jorge


Then you are mis-interpreting the results.

Bigger hash does two things:

1.  Time to depth decreases in the general case due to catching more
transpositions and having better move ordering since less gets overwritten.

2.  However, bigger hash table _also_ makes the search more accurate.  To see
this, run fine 70 with a tiny hash and with a big hash.  Big hash will let the
program find the solution _much_ earlier (in terms of search depth required).

Ignoring #2 is a bad idea.  I go for NPS and so long as increasing the hash does
not significantly lower the NPS, I go for the biggest I can get.  Too big and
the NPS drops as paging starts and that's a bad trade-off of course..




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.