This only seems to happen on occasion when accessing the inventory screen or pressing "esc" to view the achievements. The only time I was able to reliably duplicate this glitch was shortly after the Templar joined my party directly before the Leoric fight, right after the Templar joined nearly every time I would try to access a menu the screen would glitch to indecipherable levels.
The desktop I'm running is mostly salvaged from old parts of my friends gaming PCs but so far this is has only happened with Diablo 3, but it could be a personal problem; I would like to hear back if this problem is unreported elsewhere so I can work on my computer. Thanks for your time, sorry you are getting slammed on metacritic:(.
EDIT: IT WAS MY GRAPHICS CARD, /thread