In an attempt to correct a composite bug on my machine I tried installing this newer driver. This did not resolve the issue but I did find another issue. My user account was unable to starkde, as soon as I logged in from kdm the X server would crash. I traced this back to the execution of xrandr. Since this did not fix my original issue I will revert soon. To fix this I had to uncheck "Apply settings on KDE startup" in krandrtray. I will keep it installed for a bit if you need me to do anything but I plan to revert soon as there's no benefit to having an unstable driver if it doesn't fix my problem.
Gentoo Bug Report: https://bugs.gentoo.org/show_bug.cgi?id=154415
Xorg Bug Report: https://bugs.freedesktop.org/show_bug.cgi?id=8732
Steps to Reproduce:
This is probably some incompatibility with the old xrandr code. If you want to pursue it, you'll have to find or file a bug at https://bugs.freedesktop.org.