Comment 61 for bug 113679

Of course, there is a fix for that, known since more than a year. I do not know, if there is an update available for Feisty, the updated packages for Dapper have been released only recently. Obviously, the Ubuntu team does not necessarily consider this problem being important since it only crashes your X-server and causes data loss - prove them that it can be used for denial of service attacks over the network (well, it can) or even for a break-in and you'll maybe get a fix :-))

However, current Ubuntu versions come with a fixed xorg-package AFAIK, so how about upgrading your installation rather than go on waiting for an update for Feisty or replacing your video adapter?

Best regards