linux games (with nvidia) don't work anymore?

Hello,

Recently I upgraded my -current from before the threads switch. I had
some fun with libmap.conf and now things are working again, including
the nvidia driver: glxgears and the OpenGL screensavers that come with
KDE are working fine.

However, my linux games such as Quake3 and UT2004 are failing
consistently. They worked before, but now they all end up in a black
screen with the machine dead: no ping, no ssh into it.

I reinstalled linux_base (and after that nvidia-driver), but that
didn't help.

Any hints appreciated,
Karel.