Author: Jeremiah Penery
Date: 20:14:38 04/25/02
Go up one level in this thread
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. :)
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