I am in the process of running 64-bit versions of engines where possible. Naum 2.2 x64 has been completed as well as Rybka 2.3.2x64 now.
Rybka 2.3.2 32-bit seemed to significantly underperform, and indeed it's rating here is lower than on our normal blitz list. No such problems with the x64 version + 100 ELO over the 32-bit version, and the rating is now identical here to our blitz normal chess list.
http://www.computerchess.org.uk/ccrl/404FRC/index.html
Next will be Glaurung 1.2.1 x64, and that's all the 64-bit engine versions done. I tried Glaurung e5, but it has significant bugs with FRC and is not test-able.
Rybka x64 FRC testing completed - much better
Moderator: Ras