Chess rating list – anchored on Rebel 6 UCI – Pentium 90

TOP 20:

   # PLAYER                               : RATING  ERROR   POINTS  PLAYED    (%)
   1 Stockfish 17                         :   3862     17   5265.0    8370   62.9%
   2 Obsidian 15                          :   3817     23    587.0    1140   51.5%
   3 Berserk 13                           :   3793     18   3133.5    6080   51.5%
   4 PlentyChess 4.0.0                    :   3790     20    920.0    1900   48.4%
   5 Alexandria 7.0.0                     :   3764     18   2109.5    4180   50.5%
   6 Horsie 1.0                           :   3763     23    475.0    1140   41.7%
   7 Caissa 1.20                          :   3761     18   2084.5    4177   49.9%
   8 Integral 6.0                         :   3750     19    860.0    1900   45.3%
   9 Titan 1.1                            :   3743     19   1041.5    2280   45.7%
  10 Clover 8.0.2                         :   3741     18   1622.5    3420   47.4%
  11 RubiChess 20240112                   :   3729     17   1584.0    3789   41.8%
  12 KomodoDragon 1.0                     :   3718     19    760.0    1900   40.0%
  13 Seer 2.8.0                           :   3711     33    114.5     380   30.1%
  14 Koivisto 9.0                         :   3695     19   1673.5    3420   48.9%
  15 Rebel 16.3                           :   3686     24    209.0     770   27.1%
  16 Slowchess 2.8                        :   3611     36    219.0     340   64.4%
  17 Minic 3.30                           :   3502     21    659.0    1412   46.7%
  18 Black Marlin 7                       :   3469     22    681.0    1792   38.0%
  19 Arasan 23.3 NNUE                     :   3469     28    129.5     340   38.1%
  20 Fire 8.1                             :   3458     23    321.5     612   52.5%

 

Updates:

Added Obsidian 15, Horsie 1.0, Data Cash Systems CompuChess II, Fidelity Chess Challenger 1/3/7, Commodore Chessmate, Chessmaster 5000, Rebel 9, Millennium ChessGenius ARM 48 MHz..

Click here for the complete rating list:

Rating list – February 2025

The rating list – updated as of 16/02/2025 – is calculated with Ordo and was obtained under the following assumptions.

• The Elo rating of Rebel 6 UCI (1994) is fixed at 2450 points, which serves as an “anchor” for all others. This score is the average value of the results obtained by the original version of the engine in various matches against human GMs in the early 90s, derived from various official or unofficial sources (Talkchess.com, Rebel13.nl, computerchessuk.com, various forums…).
• Compared to the previous version of the rating list, the second anchor, Fritz Brains in Bahrain (emulated from Deep Fritz 8), has been removed, as it distorted the true value of the engines too much.
• Several electronic chessboards have been added whose strength in terms of Elo obtained through matches with humans is fairly well known. In this way, the rating list should provide engine scores that are more easily comparable with human ones. The electronic chessboards were emulated with CB-Emu, and made to play against several UCI and Winboard engines of similar strength.
• The time per game was set to 40/120′ repeated, reparameterized to the processing speed of a Pentium 90. The execution speed of the latter was emulated, and through various benchmarks done in the past on real P90 machines, I tried to obtain a value as close as possible to reality. Consequently, on modern PCs the actual time per game was 40/125” or 40/130” (seconds) depending on the PC used for the test, comparable to other blitz tests found on the net. For some engines, such as Chess Titans, it was not possible to define a game time; for this reason, I have indicated the characteristics of the CPU on which it was tested.
• The opening suite consists of 190 different positions, repeated for each engine (each engine played the same opening both as white and black). For older engines, not equipped with a UCI or XBoard interface (such as the 1988 version of BattleChess), I manually reproduced the various moves suggested by the programs. Also for these engines, as for all the others, the playing time was reparameterized to the performance of a Pentium 90. For this reason, the games of these engines are few compared to the total, and based on random selections of the 190 openings. The opening suite can be downloaded here.
• All the chess engines used are freely available on the net, with the exception of commercial programs that I purchased years ago, and are limited to using only one CPU core.
• In the “Top 10”, I have not included past versions of Stockfish, nor engines derived from it (such as Shashchess). In the complete rating list, I have also included past versions of Stockfish for comparison.
• The main goal of this rating list, made for my exclusive enjoyment, was both to determine the playing level of modern engines compared to past ones, but also to evaluate the actual playing strength of many programs that I loved in my youth (the aforementioned Battlechess, for example).