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Subject: Re: Hash Table Question

Author: Ray Banks

Date: 10:44:27 11/21/04

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On November 21, 2004 at 12:18:21, Joshua Lee wrote:
>Your machine defaults to 512MB but you can change it to 1GB right?
>I'm sure it can use more than even one GB but how much exactly i don't know.

Not sure, I haven't tried it.
But I seriously doubt you'd see any benefit from anything greater than 512MB
This is Fritz's help file has to say:

===========================================================================
Hash tables are memory areas in which the program can store positions and
evaluations while it is calculating the moves of a game. If the program
encounters the same position again, it can simply take the evaluation from the
hash tables, rather than analysing the position all over again.

Hash tables increase the playing strength of the program considerably. This is
especially true of tactically strong engines like Fritz, Junior or Nimzo. Some
run at well over 500,000 positions per second, and will fill the hash tables
very quickly. After that, the search slows down. This is not the case in a
slower, positionally oriented program, which processes less positions per
second, and takes much longer to fill the hash tables.

For slower time controls and deep analysis the engines need large hash tables.
Tournament games with an average of three minutes (180 seconds) per move would
ideally require over 256 MB for the hash tables. On blitz levels four to 64 MB
is enough.

Some engines work best with hash tables sizes that are powers of two. This means
that 64 MB of hash tables is much more valuable than 63 MB. Hash table sizes are
set in the "Load engine" menu.




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