I have noticed this behavoir in a few very intensive sims, like the Sim Badnarik.
When I make a turning movement, go out of mouselook, or SL is minimized or resized the SL window goes blank and freezes my whole system after I open a program or use an explorer function like Ctrl Alt Del.The SecondLife.exe process refuses to close too.
All other games/applications run fine, even GTA 4 or likewise.
My system has been reinstalled, Stress tested (Burnin test, 3dmark vantage and PC Mark).
My system seems fine, Its only SL that seems to causes these issues.
I met only one person else who had the sort of the same configuration with the same problem.
This affects all viewer versions that I tried.
This article will show you how to get detailed information about the performance of your computer and the Second Life world Statistics Bar Guide
Please try the latest RC Viewer which can be downloaded from here Release Candidate Test Viewers
If this is still an issue please Submit a Ticket with Support
for a response tailored to your individual situation see JIRA Home page
Thank you : )