X got jumpy during my Dapper -> Edgy upgrade
Xorg got really jumpy for me after my upgrade to Ubuntu Edgy. I couldn’t play DVDs fullscreen, and even some Flash animations drove the thing nuts. I poked through alot of launchpad bugs, and finally came up with a solution. I added this to the end of my /etc/X11/xorg.conf file:
Section “Extensions” Option “Composite” “Disable” EndSection
Poof, everything back to pre-Edgy wonderfulness. Obviously, composite’s got a way to go; this laptop has some serious GL hardware, and a little alpha-blending really shouldn’t be an issue.