This is an issue I had with a brand new computer but could not find anything that worked that would keep it running longer than 5 minutes under a graphic intensive load.
I have a Microtel PC, MSI motherboard, i7 3770k CPU @3.5Ghz, 32 GB ram, 120 GB SSD for primary, 2TB secondary data drive, NVidia 660 TI video card w/2GB ddr5 dram, X-fi Xtreme sound card, with a 750 watt power supply.
I had the video crashing repeatedly and had every driver updated including the motherboard bios and nothing worked. Finally by accident I switched the DisplayPort cable to an HDMI cable. I rebooted and found my video card running with no problems. I could not get the card to crash no matter how hard I tried. I sincerely hope this helps anyone pulling their hair out as I was doing for about 2 weeks.
Just tried it after reading your post and yes it is doing it again. I switched the cable with another display port cable and yet again it has crashed. Third reboot, this time with HDMI cable and it is still running. So far it still seems to be the display port. Don't know if it's the driver or the connector itself, but from what I've read on other websites, this is an issue many are having. I don't know if everyone having this issue is using the display port or not, but it seems to be working for me. I hope this helps others.