Author: James T. Walker
Date: 12:48:57 01/11/01
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On January 11, 2001 at 14:01:03, Joshua Lee wrote: >I have 256 in which i can use 128 or 184MB for hash table but untill now i was >just using 128, I can add 2 256's so 768MB as far as i know if you double the >hash size you are supposed to get 8elo points so what an extra node or two >pretty much but besides this in the fritz manual you multiply Processor speed x2 >then X the number of seconds per move in the time control so for instance > >800x 2 1600 x 180 (for tournament time) = 288000 /1024 281.25 so fritz >apparently needs 281 MB for Hash Tables > >For analysis it would fill 768MB in 8minutes 1600 x 480 =768000 but what i am >trying to understand is how exactly does this make a difference when each double >nets 8elo Fritz would play 16elo points better???? > >This 8elo point figure was old maybe since times have changed there being faster >memory this has changed. > >Other than that what would the Depth Differences be? with 128MB Fritz usually is >around 14Ply in 3Min. Will it get 1 or 2 extra? > > >Thankyou Hello Joshua, I have done a little testing in this area but my memory is gone. You can test these things yourself. I think you will find that in the early middle game the hash tables make very little difference in a 3 min search. Maybe a few seconds. As you get farther into the game with less pieces on the board the hash tables become more and more effective. I have seen a difference of 3 ply in the endgame for hash tables vs no hash tables. The 8 elo was an old estimate and may still hold up for approximation. The formula in the Fritz manual is basically for computing the 'minimum' hash table size. There is nothing wrong with having a little more. If you are expecting a big jump in strength for doubling your hash you will surely be disappointed. If the only reason you are buying it is for your chess program I would advise you to save your money. I have 256 meg in both of my machines and I feel very comfortable with it. I might add that I don't do much overnight analysis where extra ram would be more useful. Jim
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