I can recall moments when crashes stopped but can't recall whether my ,,Enable Open Gl,, was on or off. It is on at the moment so I will turn it off and see how it goes. The other thing I would like to point is I can observe slight lug too and when I log into task manager I can see that CS5 uses nearly 4GB RAM(over assigned limit!) while I have only couple of layers in CS5 no smart objects , no any kind off 3D work going on just simple retouch when before I would have like 20-40 layers and task manager would show only 1.5-2 GB used by photoshop. I wonder how does it come such a big amount of RAM being used for simplest task. In preferences panel ideal RAM recommended range is 2903-3800 MB
I assigned 3600MB in ,,let photoshop use,, (68% of the total available RAM on PC.
Hope this will give some clues too.