when i use a compositing window manager, like compiz or activating the composite option in metacity, i cannot seem to use any kind of OpenGL application (glxgears, chromium, alienarena, ioquake3, ...) anymore. What happens is that the applications nearly eats up all available CPU time, while providing a slide show at best. Trying to run glxgears for example gives an astonishing ~0.5 fps, whereas running glxgears without a compositing WM active gives about 2900 fps.
X.Org X Server 1.4.2,
nvidia driver 96.43.07 from up-to-date ports collection
NV28 (GeForce4 Ti 4200 with AGP8X)