Xorg hungup on GeForce GTX 680 and 387.12 driver

Hello,

Xorg is totally hungup randomly. In logs:

kernel: nvidia-modeset: Allocated GPU:0 (GPU-adb1c4d5-88a4-5f2f-30af-a3f8276e5e40) @ PCI:0000:01:00.0
kernel: NVRM: GPU at PCI:0000:01:00: GPU-adb1c4d5-88a4-5f2f-30af-a3f8276e5e40
kernel: NVRM: Xid (PCI:0000:01:00): 79, GPU has fallen off the bus.
kernel: NVRM: GPU at 0000:01:00.0 has fallen off the bus.

nvidia-bug-report.log.gz in attach. Please help!

Thank you.
nvidia-bug-report.log.gz (146 KB)

Can you help please?

XID 79 is often connected with overheating or failure of power source. Use nvidia-smi to monitor temperatures in the background to see if this is the case.