The answer: it depends on the terrain.
Last week I posted that Fire 2.2 won by a big margin over Stockfish 2.3.1 when both were compiled with the same compiler and build parameters in 32bit mode. I attempted to have a rematch for them, this time with 64bit compilation. The first 20 games phase of the match showed Fire leading comfortably, but then my computer showed signs of abnormal performance, which made me remove the 2 other tournaments running under Arena leaving only Fire vs. Stockfish, to diagnose the perceived problem. As I observed, I noticed that Stockfish is steadily winning games and saw that the KN/sec speed of Stockfish is on par with Fire which was lower before. To confirm my suspicion, I restarted the other stopped tournaments and saw that Fire is steadily regaining the lost games and at the same time the KN/sec is higher in Fire's. Then my computer crashed hard...
To verify what I just observed, I ran the tournament of Fire vs. Stockfish in a separate computer running with AMD dual core 2800ghz, clearing all the other programs. My suspicion was confirmed that Stockfish is better in conditions when there are no other major processes that will hog the CPU processor.
I made another compilation this time with Firenzina 2.2.2 xTreme in 64bit which was intended to be used in my rating tournament because the author has no 64bit version that will run in my computers. This was an opportunity to test it against the formidable Stockfish 2.3.1 stable version compiled by Jim Ablett. It is an Intel vs Intel C++ Compiler classic battle which would provide some clue on whether Stockfish is supreme in the open-source chess engines. I ran the tournament in my restored computer that crashed, an AMD Quad Core which also has other 2 tournaments running simultaneously. The result was a 55-45 win for Firenzina which was hurriedly posted to chess2u.com forum to update my posts there, then went home to rest. The following day, I noticed that I picked the wrong version of Stockfish which was a 32bit compilation. With apology, I restarted a rematch to correct the blunder, this time in two separate computers with the one running in the same AMD Quad Core with 3 simultaneous tournaments and the other in an AMD Dual Core with only 1 tournament running.
Here is the scoreboard:
|Engine||AMD 4 Core||AMD 2 Core||Total Points||Ave%|
|Stockfish 2.3.1 x64-ja||26||58.5||84.5||42.25|
|Firenzina 2.2.2 xTreme x64-owl||74||41.5||115.5||57.75|
From the results, it could be said that Firenzina is the better engine. But, it depends on what environment the tournament is run and probably the factor of the referee.
This is something for the Stockfish Team to verify and counter-check. The main issue is that Stockfish seems to starve when there are lots of simultaneous threads running.
And the final answer of who is better? Oops, the referee is gone...
Download the Firenzina 2.2.2 x64 owl version used in the match here.
Download the tournament results here.