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Subject: Is more hash better? My tests say the opposite...

Author: William Penn

Date: 16:44:28 08/31/03


The more hash I allocate, the slower the kN/s speed. Thus 4MB (the minimum) is
the fastest in my tests, typically about 450kN/s. If I increase that to say
256MB hash, the speed slows down to about 400kN/s. The more I increase hash, the
slower the kN/s speed.

The kN/s speed peaks, then eventually starts to decrease. How long this takes
depends on the amount of hash. However in my tests, the long term speed
advantage of bigger hash never catches up with the long term speed obtained with
smaller hash. Thus I don't see any advantage whatsoever to using a hash table!
The opposite seems to be true!?

I'm using the Shredder7 GUI, Shredder 7.04 UCI engine, AMD XP Athlon 2400+/640MB
RAM (608MB available). The GUI says the maximum I can allocate to hash is about
455MB, so I'm not near the limit. Of course I'm using fairly common practical
positions for these tests in Infinite Analysis mode, and the above indicated
results are typical.

I get very similar results running Shreddermarks with different size hash. The
more hash, the lower the Shreddermark and corresponding kN/s.

Now, will someone please refute this, or explain what I'm missing or
overlooking? Thanks!
WP



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