This sounds similar to bug https://bugs.freedesktop.org/show_bug.cgi?id=9711, although the symptoms as described are a bit different.
-- [Gutsy] corrupt graphics off live cd with mga AGP450 Dualhead https://bugs.launchpad.net/bugs/110489 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs