Ok, lets try this. If you want to upgrade to windows 8, go ahead and do so. This time, let windows 8 install all available updates as Bora suggested, it will install the version of AMD's graphics you spoke of, run that version for a bit, if it is not up to the task, then use AMD's website to install latest version, it will offer to uninstall the other version before upgrading. Try tweaking some of the settings in the catalyst control panel, adjust your power settings to performance "if available", and go from there.