Well usually in oss mode if you hear one (or did you install 32 bit libs for alsa?) - thats no good comparision. Also I found out that the Debian sid package of nexuiz was compiled with debug and that was much slower than the "official" one. Saidly this was compiled with a too new glibc 2.4 - other games like sauerbraten would work directly with the official packages. Therefore I disabled now the debug mode for the Kanotix repository - you can expect up to 40% speed improvement when you formerly used the sid package (or an unmodified backport).