Manual de Fritz 15 2015 | Page 253

Reference

253

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 16 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.

Some technical notes
The Windows operating system takes unused memory and uses it for internal
purposes (e.g., to cache file and speed up the hard disk). If you set very large hash
tables, Windows has to free the memory the first time you activate the engine. To do
so, it writes the contents to the hard disk, closes files, etc. The process can
sometimes take a while, and during that time the hard disk will run constantly.
After the memory required for the hash tables is free the hard disk should show no
more activity (except for short seeks in the openings). This applies to subsequent
games as well.
If there is constant disk activity during the game, then the hash tables you have
set are too large. Windows has installed part of the tables on your hard disk, which
slows the program down drastically. You will notice that the search depth remains very
low.
If there is no disk activity at all when you first start an engine, this generally
means that you have been too timid with the hash tables size. You may want to
increase the size to get optimum playing strength.
If you are playing an important tournament game with large hash tables, you
should start the engine once to force Windows to release the required memory. Press
Alt-F2 to start the engine, and Alt-F2 again to stop it when everything is quiet.

3.8.8

Engine management
E ngine

E ngine m a na ge m e nt

One of the great strengths of the ChessBase programs is that there is a strict
separation between the interface, which provides the graphics and functionality, and
the chess engines, which calculate the moves. This makes it possible to provide many
interesting chess engines by talented programmers all over the world. The authors
themselves do not have to bother about the interface, they can concentrate fully on

© ChessBase 2015