Twenty-two games added from Ladder Challenges #43 and #44. New total 886. Engines with less than 30 games shown separately.

7-Zip file can be downloaded (compressed, but still 5.8MB).

All games show current ratings, if over 3000. Principal variation included in game output.

Regards.

3pm Monday, 7th March 2011 (UTC+0/GMT).

Deep Rybka 4 (3211) v Houdini 1.5 (3265), game eleven.

Houdini leads 5.5-4.5 in its bid to regain top rung of Ladder.

Twenty-four games added (from Ladder Challenges #41 and #42). Total 864 . Engines with less than 30 games shown separately.

7-Zip file can be downloaded (compressed, but still 5.7MB).

All games show current ratings, if over 3000. Principal variation included in game output.

Know sample size ...

[...] Did either have tablebases? [...]
Both used tablebases.

After the game, got DR4 to analyse position prior to Bb8 and it immediately found f3 (as did Houdini, IvanHoe and Critter).

In the game, DR4 had 15' 14" on the clock and took 3' 44". Furthermore, its own evaluation of Bb8 was that of ...

[Event "Ladder Match 41 12g max Feb 2011"]
[Site "Intel Core i3-330M"]
[Date "2011.02.19"]
[Round "5"]
[White "IvanHoe 47"]
[Black "Deep Rybka 4"]
[Result "1-0"]
[WhiteElo "3244"]
[BlackElo "3202"]
[TimeControl "5400"]
[SetUp "1"]
[FEN "8/8/5p2/5kb1/P1R1p2p/8/1P6/3K4 w - - 0 38"]

Turnarounds
1 ...

Ratings updated after 84 games added. Now 840 in total, each with a time control of 90 minutes each side. Principal variation included in game output. 7-Zip file can be downloaded (compressed, but still 5.6MB). Know sample size is small.

Engines with less than 30 games shown separately.

[...] See this thread: http://www.open-chess.org/viewtopic.php?f=4&t=791
I do, now, see a potential problem with Ponder on, but only because of Intel® Smart Cache (ISM).

Without ISM, an engine limited to one core would not be able to spill over into the second core's cache.

Potential problem ...

Not a good idea in my view to run ponder-on games on the same hardware. If it were say a quad-core and each engine is running single core, or hexa-core with each engine using dual-cores, then it should be fine.
Each engine gets a single core , each core having two hardware threads.

Are you saying ...

Deep Rybka 4 moves to third on ladder after finishing 6.5-2.5 ahead of Stockfish 2.0.1.

kingliveson wrote:[...]
Is this running on 2 different hardware, or single with 2 cores per engine?

One laptop, with CPU having 2 cores and 4 hardware threads. Each engine gets two hardware threads.