Author: Uri Blass
Date: 22:05:01 04/25/02
Go up one level in this thread
On April 25, 2002 at 23:14:38, Jeremiah Penery wrote: >On April 25, 2002 at 13:33:03, Robert Hyatt wrote: > >>take Crafty, use the default hash, and search for (say) 5 minutes, a typical >>search for 40/2hr time controls. Then double the hash and try again. And >>double and try again. The time required for the search will vary from 2x-3x >>(or more)... In middlegame positions. >> >>I posted some test results like this several years ago in r.g.c.c when >>KomputerKorner asked me to run the test to give some real answers on how >>hashing affected middlegame positions. The answer was more than I thought. > >I actually remember it being less than expected - I've found the link: > >http://groups.google.com/groups?q=crafty+hash&hl=en&selm=7b1o5j%24qhm%241%40juniper.cis.uab.edu&rnum=3 > >[D]3rr1k1/1p2b1pp/p1b1p3/8/PnBBq3/2Q2N2/1PP3PP/R4R1K b - - 0 1 > >This position was searched to 11 ply (Crafty version unspecified), here are the >results for different hash sizes: > > hash table sizes >time bytes entries nodes searched >------------------------------------------- >13:13 96kb 6K 157,085,451 >12:03 192kb 12K 142,633,162 >10:31 384kb 24K 123,762,238 > 9:28 768kb 49K 110,838,220 > 8:38 1.5M 98K 100,802,339 > 7:48 3M 196K 90,979,000 > 7:22 6M 392K 85,975,960 > 6:53 12M 800K 80,347,212 > 6:32 24M 1.5M 76,465,119 > 6:22 48M 3.0M 74,738,532 > 6:13 96M 6.0M 73,253,374 > 6:05 192M 12.0M 71,581,397 > 6:03 384M 24.0M 71,156,722 > > >So about 12 doublings in size give a speedup of slightly over 2. That's not >such a huge amount. :) Thenks for the information. It suggests that 6-7 elo from doubling the hash size is really close to the truth. There is a big difference between 6K and 24M but there is not a very big difference between 6M and bigger hash tables and in my case I guess that there is not very big difference between 8M hash for chezzz and bigger hash tables. Uri
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