Chess-Playing Software

The strength of chess-playing software is highly dependent on the hardware it runs on (all software discussed is for MS-DOS; programs available for MacOS are noted). Here is a method to approximate the strength differences for the same software running on different hardware (source: _Computer Chess Reports_).

Processor "Chess MIP's"

8088                      Speed in MHz divided by 19
80286, 1 wait state       Speed in MHz divided by 8
80286, 0 wait states      Speed in MHz divided by 6
80386, no cache memory    Speed in MHz divided by 6
80386 with cache          Speed in MHz divided by 4.7
80486                     Speed in MHz divided by 2.3
(Note that math coprocessors--used before the 486--don't change the speed, since chess programs don't use floating point arithmetic at all.)

Now, if a program has a given rating on a 1 (Chess) MIP machine, this is how to adjust the rating for other MIP's (interpolate between points):

MIP:  0.25 0.5 1 1.5  2  3   4   6   8   12  16  24  32  48  64
Adj.: -180 -87 0  47 80 124 154 195 223 261 287 323 347 379 402

For example, a program running on a 10 MHz 8088 (0.5 MIP's and -87 points) will be about 272 USCF rating points weaker than the same program running on a 33 MHz 80386 (no cache: 5.5 MIP's and +185 points).

CCR Ratings List PC Program Ratings

Ratings are the average of autotest at 30" to 1' per move, Computer Chess News Sheet from England and the "Ply" list from Sweden. PC programs are rated on an i486 PC running at 33MHz. See the Volume 3, Number 2 issue of _Computer Chess Reports_ for more details.

Available for MacOS: Chessmaster 3000 & 2100, Sargon IV (V due soon), BattleChess and CheckMate. Available for the Amiga: Chessmaster 2000 and 2100, Sargon III and IV, Chessplayer 2150 and Chess Champion 2175, BattleChess and CheckMate, ChessMate, The Art of Chess, Colossus Chess and the ChessMachine.

Gnuchess is a freely available chess-playing software program (see [18]). Its strength varies widely based on the machine for which it's compiled.