Xen and NVidia

[RavenOak]

I'm trying to get Xen and the NVidia binary driver to work properly.  3d
accel seems very slow.  At the moment I'm using the driver package from
FreshRPMS (nvidia-x11-drv-97xx-1.0.9762-4.fc7), and it compiles fine,
loads X fine; but when I have Compiz enabled, rendering is *very* slow.
The only reason why I'm using 97xx is that the newest driver does not
seem to play well with Compiz, it crashes the entire system (thanks
NVidia for inserting a display driver directly into the kernel ;) when I
attempt to logout or stop Compiz.  Do I need to use the 'nosegneg'
work-around for glibc?  Or if newest NVidia driver will work, how do I
get around the logout/stop Compiz crash?

Any suggestions would be welcome (other than "don't do that..." without
proper explanation to back it up).

Thanks,
Tim