I have same problem with amd64 and Nvidia 8800GTX. Also I have a message in "Additional drivers": "This driver activated but not currently in use" (screenshot added). Possible, it is source of problem. And temperature of my video, I think, too high - 83C (in 3D games under Windows maximum, what I seen - 76C).
** Attachment added: "Drivers.png" https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/772994/+attachment/2098999/+files/Drivers.png -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to nvidia-graphics-drivers in Ubuntu. https://bugs.launchpad.net/bugs/772994 Title: After 10.10 upgrade to 11.04 there is no visual effects _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp