It is a driver problem. However, to fix it you need to completely uninstall the problem drivers (12.2) and then install a fresh set of drivers (NOT 12.2, obviously!). If you don't know how to do that, follow the directions http://www.gamesas.com/topic/1368527-graphic-issue-pixelated-like-image/page__view__findpost__p__20665695
FYI I can't really recommend 12.4 right now...I haven't tried them myself, and people are reporting FPS loss and a few other issues. You may prefer to install 12.3 or even 12.1.