I’ve experienced this about 6-7 times so far, a few times after I pressed Shift+Space and it started to render again the viewport (a couple of seconds later).
Viewport in Cycles render mode.
Blender 2.67b
Win 7 SP1
Intel Core 2 duo @ 2.4GHZ
4GB RAM
Monitor res 1920 x 1200
Nvidia GTX 560 Ti
Thanks but this is the first case shown, so the second is obviously due to something else.
(While you were posting I was struggling to update the post with the two different attachments -the attachment code is buggy).
I don’t like to be a harbinger of doom, but unfortunately if you’ve put the tdr delay thing up high already, I think this is bad sign hardware wise, well if it gets to the BSOD stage (which mine is) anyway :(.
Having said that, the frequency of it happening to me did seem to dramatically increase with the latest nVidia drivers - so maybe there is still (some) hope for me, though I’m getting a new gfx card soon anywayz.