Comment 9 for bug 888039

I see this bug on both an intel system and an nvidia system as well. The benchmark that shows the degradation is glxspheres, available in the virtualgl package (which is installable via apt-get if you do sudo apt-add-repository ppa:mj-casalogic/ironhide). glxspheres drops from around 60 fps to as low as 25 fps when the degradation is apparent.

I notice the opposite in RAM usage, however - compiz typically is using less RAM when I see the degradation. And it often comes on quite quickly. It might be related to having a few windows open (I typically run Netbeans, VirtualBox, Firefox, Thunderbird) or it might be related to using a lot of RAM. Sometimes the degradation persists across multiple reboots (and for multiple users), but when this happens there is never any degradation using metacity or mutter.

I've documented a lot of what I've tried at bug #861061 and how the problem sometimes randomly resolves itself.