[gentoo-amd64] Bad performance on doom3 with alsa and oss

[Etienne Imguimbert]

Dear gentoo amd64 users
I've installed doom3 via the emerge command, and I have several problems of
performance. I tried several configurations:
- when I switch to alsa in doom3, I get very noisy sounds (I get several
messages of rejected packets by alsa in the shell)
- when I switch to oss, I get huge slowdowns in the game (I think there is a
problem with the OSS emulation by alsa)
- when playing timedemo demo1 in the doom3 prompt, I get a good number of
fps (about 60), but this benchmark is played without sound, so I deduce that
I have problem with sounds.

All other sound apps work fine (like amarok, kscd).

In the kernel configuration, I did not configured any alsa or oss support,
just the sound support, and I installed alsa by the emerge command (the
version emerged is 1.0.10, the latest stable in portage).
I've read somewhere that the command: echo 1024 >
/proc/sys/dev/rtc/max-user-freq  would produce better synchronisation, but I
didn't change anything for me.

My question is finally how to get good sounds in doom3 using alsa, not oss
emulation.

Thank you very much

Best regards,

Etienne