Comment 2 for bug 1198048

On the graphics side of things, your AMD/ATI Radeon 7500M/7600M "Thames" may be getting too hot. You can enable power management for it by using one of the methods described at http://xorg.freedesktop.org/wiki/RadeonFeature/#index3h2

The first two methods are only rudimentary but are available now. The 3rd (dpm) method is much better and is available (for AMD/ATI Radeon R600 and newer hardware) in the upstream 3.11 linux kernel. The third release candidate (3.11-rc3) of the 3.11 kernel is available at http://kernel.ubuntu.com/~kernel-ppa/mainline/ and instructions on how to install and uninstall it are available at https://wiki.ubuntu.com/Kernel/MainlineBuilds

To use this power management for the AMD/ATI Radeon you will need to select it at boot by adding radeon.dpm=1 to your GRUB kernel boot options as described at https://help.ubuntu.com/community/Grub2/Troubleshooting#Editing_the_GRUB_2_Menu_During_Boot

To use the new power management feature on R700 and newer hardware (other than APUs) requires installation of the latest AMD graphics microcode (ucode) files to /lib/firmware/radeon
These are available at http://people.freedesktop.org/~agd5f/radeon_ucode/
Get the version ending in "smc".

R700 basically means Radeon HD 4000 series and newer. However note that according to Wikipedia and http://xorg.freedesktop.org/wiki/RadeonFeature/#index5h2 the Mobility Radeon HD 4225/4250 is a RV620 chip, so anyone with one of those shouldn't need the updated firmware files.

See the blog post at http://www.botchco.com/agd5f/?p=57 for further information.

Unlike the older dynpm method, the new DPM method works with multiple monitors and there shouldn't be any flickering as the performance level changes are handled by dedicated hardware rather than the driver.