Only 15 Elo over its predecessor.

Sorry, but there is a bug in the 1.2 that can cause problems with position with blocked pawns structure.
There is the update 1.2b available https://sites.google.com/site/mdannib/download

Regards

Mortal_Sin

@Nicolas wrote:Only 15 Elo over its predecessor.

If you run games only between the new version and the old one; have you tried with other opponents like stockfish?

being tested in IPON
BlackMAmba

BlackMamba_1.2b - Houdini 3 STD (3090) 4.0 - 16.0 20.00% Perf=2850
BlackMamba_1.2b - Komodo 5 (3007) 5.5 - 14.5 27.50% Perf=2839
BlackMamba_1.2b - Critter 1.4a (2986) 8.0 - 11.0 42.11% Perf=2931
BlackMamba_1.2b - Stockfish 2.2.2 JA (2968) 8.5 - 11.5 42.50% Perf=2916
BlackMamba_1.2b - Deep Rybka 4.1 (2963) 8.0 - 11.0 42.11% Perf=2908
BlackMamba_1.2b - Chiron 1.5 (2851) 11.0 - 8.0 57.89% Perf=2906
BlackMamba_1.2b - Naum 4.2 (2840) 11.0 - 8.0 57.89% Perf=2895
BlackMamba_1.2b - HIARCS 14 WCSC 32b (2824) 11.0 - 8.0 57.89% Perf=2879
BlackMamba_1.2b - Gull 1.2 (2801) 12.0 - 7.0 63.16% Perf=2894
BlackMamba_1.2b - Deep Shredder 12 (2800) 15.0 - 4.0 78.95% Perf=3029
BlackMamba_1.2b - Hannibal 1.2 (2801) 12.5 - 5.5 69.44% Perf=2943
BlackMamba_1.2b - Deep Sjeng c't 2010 32b (2792) 13.0 - 7.0 65.00% Perf=2899
BlackMamba_1.2b - Spike 1.4 32b (2780) 14.5 - 4.5 76.32% Perf=2983
BlackMamba_1.2b - spark-1.0 (2771) 13.0 - 4.0 76.47% Perf=2975
BlackMamba_1.2b - Protector 1.4.0 (2763) 13.5 - 5.5 71.05% Perf=2918
BlackMamba_1.2b - Deep Junior 13.3 (2755) 13.0 - 5.0 72.22% Perf=2920
BlackMamba_1.2b - Quazar 0.4 (2736) 15.0 - 2.0 88.24% Perf=3086
BlackMamba_1.2b - Zappa Mexico II (2709) 15.0 - 4.0 78.95% Perf=2938
BlackMamba_1.2b - MinkoChess 1.3 (2701) 16.0 - 2.0 88.89% Perf=3062
219.5 - 138.5 61.31% Perf=2920




358 out of 2850 games played
Level: 5 Minutes/Game + 3 sec/Move

But I only wonder why they still use Gull 1.2 when there is Gull 2

The new version 1.2c is ready; this is a bug fixing release.

The change log :
- Fixed the bug that cause random crashes during endgame (thanks Ingo)
- Fixed time manager bug that occurs on long time control
- Fixed an annoying bug that "freeze" the engine at 7ply on certain positions
- Tuned evaluation
- Tuned the limit strength feature (too weak compared to the elo settings)
- Fixed misevaluation due to pawn blockages on some positions

Regards,
/Matteo & Maurizio