Fedora Kernel and Audio Latency Problems

[dragoran]

Hello.
I am using kernel-2.6.12-1.1398_FC4.
I tryed to play doom3 with 5.1 Sound and got this Problem:
idAudioHardwareALSA::Write: 4096 frames overflowed and dropped
and hear no sound.
doing
echo 1024 > /proc/sys/dev/rtc/max-user-freq
solves the problem.
Why is this default to 64?
Would (voluntary/realtime) preemt solve this issue too?
If yes why did voluntary preemt dissappeard from the FC kernels?