Conditions:
AMD Opteron 1352 2.1GHz
Shredder GUI
Time control 1 Minutes/Game + 1 Seconds/Move
100 randomly selected opening positions with switched sides
Each engine one thread
Ponder ON
256MB hash
5-men tablebases
Results
Rybka 4 x64 763.0 / 1000
Stockfish 1.7 x64 658.5 / 1000
Naum 4.2 x64 532.5 / 1000
Shredder 12 489.0 / 1000
Hiarcs 13.1 295.0 / 1000
Sjeng WC2008 x64 262.0 / 1000
BayesELO Ratings calculation:Rank Engine ELO + - Score AvOp Games
1 Rybka 4 64-bit 3296 +18 -17 76.3% -209.8 1000
2 Stockfish 1.7 64-bit 3226 +17 -17 65.8% -125.8 1000
3 Naum 4.2 64-bit 3144 +17 -17 53.2% -27.4 1000
4 Shredder 12 3116 +16 -16 48.9% +6.2 1000
5 Hiarcs 13.1 2987 +17 -18 29.5% +161.0 1000
6 Deep Sjeng WC2008 64-bit 1CPU 2958 +18 -18 26.2% +195.8 1000
This was just a bit of fun, but also I was interested to see if Rybka 4 performed as well at chess960 under these conditions ("game in x minutes" time control with increment, and ponder on) as it did in the CCRL 40/4 repeating tests with ponder off. It seems that it does. If we take the gap betwen Rybka 4 and Stockfish 1.7:CCRL 40/4 FRC list - gap = +73 ELO
This round-robin - gap = +70 ELO
The gap is almost identical, so my conclusion would be yes, despite the very different test conditions, Rybka 4's chess960 performance is similar.
The pgn is attached in case anyone is interested in the games.
This was something different and a bit of fun, I'll now think about another chess960 tournament of some sort.