Not entirely sure, I think if you have enough airflow in the case, fans might not spin (looking at your temps, your GPU is very cool, so maybe fans are off to not waste any power) If you were running GPU @ 75+C and fans didn't spin that would be a problem.
the only question I have is why is there such a huge spread? almost 10 degrees is a lot, does it really vary that much under load?
windows power settings can be accessed from control panel it's called "Power Options" or you can type in power options to start menu that always works (this new features I simply love about win7)
ok with that resolution I think your 560 should have zero problem running everything on ultra. So, I think you have something like screen saver kicking in maybe?
Double check your video cable connection to the GPU port