Here are some results of my testing. Note that I have played several thousand games at tournament timecontrol to adjust the strenght in order to the old SSDF ELO values which appeared to be very close to human values. Except the matches against Roma and Rebel the adjusted ELO values are very close to the SSDF values (+/- 10 ELO).

Between 2000 and 2600 ELO doubling the speed of SlowChess makes it play stronger by 65 ELO. Between 1000 and 2000 ELO doubling the speed incrases the ELO by up to 112 ELO.

Now to the tests of the final version, the opponents with official SSDF ELO values:

1464 ELO Mephisto III*
1824 ELO Rebel 5 Emulation
1904 ELO MM IV Emulation**
1971 ELO Dallas Emulation
1974 ELO MM V Emulation**
2030 ELO Roma 32Bit Emulation
2445 ELO Resurrection Fruit 2.1***



                               Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mephisto III                1464  27,5 / 50   11011111011=10=11001=100=00=10011=1=0=10010001=011   1500 +25
 2: Mysticum SlowChess ELO 1464 1464  22,5 / 50   00100000100=01=00110=011=11=01100=0=1=01101110=100   1428 -25
----------------------------------------------------------------------------------------------------------------
50 games: +24 =9 -17

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 1824 1824  32,5 / 50   =01=10110111101=0110110=110=1=101111=1011011100110   1934 +75
 2: Mephisto Rebel 5            1824  17,5 / 50   =10=01001000010=1001001=001=0=010000=0100100011001   1714 -75
----------------------------------------------------------------------------------------------------------------
50 games: +24 =7 -19

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 1769 1769  25,5 / 50   100=11=11001====101=010=10=1010=0011110001010101=0   1831  +5
 2: Mephisto Rebel 5            1824  24,5 / 50   011=00=00110====010=101=01=0101=1100001110101010=1   1817  -5
----------------------------------------------------------------------------------------------------------------
50 games: +16 =11 -23

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mephisto MM IV              1904  26,5 / 50   0010===10011=011011011=011101==01001001=1011=01==0   1925 +15
 2: Mysticum SlowChess ELO 1904 1904  23,5 / 50   1101===01100=100100100=100010==10110110=0100=10==1   1883 -15
----------------------------------------------------------------------------------------------------------------
50 games: +22 =11 -17

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 1927 1927  26,5 / 50   0011100=01=11100001=0=11==1===1==11=001=1====01001   1948 +15
 2: Mephisto Amsterdam          1927  23,5 / 50   1100011=10=00011110=1=00==0===0==00=110=0====10110   1906 -15
----------------------------------------------------------------------------------------------------------------
50 games: +22 =17 -11

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mephisto Dallas 16Bit       1971  25,0 / 50   ===11==110=1=1111=01==0=100100000011=0=011=0000110   1971  +0
 2: Mysticum SlowChess ELO 1971 1971  25,0 / 50   ===00==001=0=0000=10==1=011011111100=1=100=1111001   1971  +0
----------------------------------------------------------------------------------------------------------------
50 games: +25 =14 -11

                                Rtng    Score     1234567890123456789012345678901234567890123   Perf Chg
---------------------------------------------------------------------------------------------------------
 1: Mephisto MM V               1974  22,0 / 43   1=1011101011=001010011=0110=0=000==11=00011   1981  +4
 2: Mysticum SlowChess ELO 1974 1974  21,0 / 43   0=0100010100=110101100=1001=1=111==00=11100   1967  -4
---------------------------------------------------------------------------------------------------------
43 games: +18 =8 -17

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 2030 2030  29,0 / 50   ==10011=1011=0=01=1=101001=1111=1=1=1=0=11=0001010   2087 +40
 2: Mephisto Roma 32Bit         2030  21,0 / 50   ==01100=0100=1=10=0=010110=0000=0=0=0=1=00=1110101   1973 -40
----------------------------------------------------------------------------------------------------------------
50 games: +16 =14 -20

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 2011 2011  25,5 / 50   0110==010===1=11010=010==1100101010100110=10=10110   2037  +5
 2: Mephisto Roma 32Bit         2030  24,5 / 50   1001==101===0=00101=101==0011010101011001=01=01001   2023  -5
----------------------------------------------------------------------------------------------------------------
50 games: +22 =11 -17

                                   Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
-------------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 2445    2445  26,0 / 50   1001==01010=10=00110==0011=1=1=110==101=0=10=11==0   2459 +10
 2: Resurrection Fruit 2.1 203 MHz 2445  24,0 / 50   0110==10101=01=11001==1100=0=0=001==010=1=01=00==1   2431 -10
-------------------------------------------------------------------------------------------------------------------
50 games: +22 =16 -12


Because the values did not fit for fast games I did some adjustments at fast timecontrol, here SlowChess calculates faster at weak levels, and slower at high levels.


                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mephisto III                1464  27,5 / 50   0011101011===001011011101011101=1010000=1111100=0=   1500 +25
 2: Mysticum SlowChess ELO 1464 1464  22,5 / 50   1100010100===110100100010100010=0101111=0000011=1=   1428 -25
----------------------------------------------------------------------------------------------------------------
50 games: +28 =7 -15

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 1824 1824  28,5 / 50   0=1111=1=11==0=1011=0010=0=111110110==110010000101   1874 +35
 2: Mephisto Rebel 5            1824  21,5 / 50   1=0000=0=00==1=0100=1101=1=000001001==001101111010   1774 -35
----------------------------------------------------------------------------------------------------------------
50 games: +21 =11 -18

                                Rtng    Score     12345678901234567890123456789012345678901234567890   Perf Chg
----------------------------------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 2030 2030  26,0 / 50   1111000000111001010==1111101010=0101=0==1101000101   2044 +10
 2: Mephisto Roma 32Bit         2030  24,0 / 50   0000111111000110101==0000010101=1010=1==0010111010   2016 -10
----------------------------------------------------------------------------------------------------------------
50 games: +31 =6 -13



A quick test of SlowChess 1000 ELO against Microchess 1976, just to be sure that SlowChess 1000 ELO is able to lose against this weakest thing available:

                                Rtng    Score     12345678901234567890123   Perf Chg
-------------------------------------------------------------------------------------
 1: Mysticum SlowChess ELO 1000 1000  18,0 / 23   =1=1=10111=111011111110   1310 +94
 2: Microchess 1976             ????   5,0 / 23   =0=0=01000=000100000001    780 -94
-------------------------------------------------------------------------------------
23 games: +11 =4 -8

It is hard to classify ELO values of 1000, so maybe at this level the values are not exact.


*Mephisto III = The Glasgow Emulation at 3,05 MHz. (Mephisto III runs at 6,1 MHz, the Glasgow Emulation is 2x faster because it is 16Bit instead of 8Bit)
**The MM Emulations where not able to play all games because they hang at some positions. Thats why there are less than 50 games.
***Resurrectiion Fruit 2.1 = Fruit 2.1 at the speed of a Resurrection 203 MHz. In the middlegame it plays like the Resurrection, in the endgame it is 5-6% faster which should not have much influence on the strength. The Resurrection Fruit `05 is listed in the SSDF list with 2395 ELO. Fruit 2.1 is around 50 ELO weaker in all ratinglists. Because the SSDF once reduced all ELO values by 100 I have to add this 100 ELO again. So this version should have quite exactly 2445 SSDF(old) ELO.