This happens to me too, and also, as Raze said, when I am overzealous in my attempts to get better stats for a weapon or an amulet.
Actually, I found that the true solution to this problem is very simple. No need to reinstall the game or look for newer drivers (mine are newest anyway).
Just, when at the restarting the game it would wish you to reset the configuration, select NO. Apparently, it feels comfortable with the "old" configuration prior to the "blank minimap" state. After that the game runs quite smoothly (till the next fit of excessive reloading, that is).
Try it: works for me.