Not sure if this is the place for it... Recently my Photoshop CS5 have been giving me some issues. It will lag up while painting with just a standard brush. These random square distortions will show up, then go away after a few more brush strokes. I've attached an image depicting what this looks like.
AMD Phenom II x4 3.4
HIS HD 5770
8GB DDR3 RAM
WD Black 750GB HD
All drivers are up to date. Perhaps I have the graphics settings too high? Or maybe I need to disc defrag.