Running a fresh install of Win 10. But I upgraded from a GTX650 to a GTX960 SSC.
Before when I watched movies with VLC player in full screen -- the monitor wouldn't sleep.
Since I have upgraded the video card, the monitor goes to sleep 10 minutes in. With VLC player.
Even if I set the monitor to NEVER SLEEP in the power options... it still goes to sleep.
I checked motherboard bios, no strange power options there.