I am having similar Nvidia driver issues. 285.62 on SLI GTX 580's. SU works fine (but slooow) with hardware acceleration, Fast Feedback unchecked. As soon it is switched back on SU freezes (entire computer) within one or two minutes. I have even tried setting up a custom program control in Nvidia's control panel under 3D settings, adding Sketchup to the programs list and customizing based on other users successful use of Quatro settings. NO LUCK. It is my understanding that Nvidia, at least at one time had been certified for use with Sketchup?
Aside from waiting for a new driver, any suggestions?