Blue Screens, Freezes, and System Clock Issues

I recently installed a z77 Pro3 and i5-2500k into my system. Up until this point my (slow) machine had been running just fine. Now, even with a new install of Windows 8, I'm getting crashes, freezes, and issues with the system's clock.

For starters, the clock will not tick in the UEFI menu. It often rolls back a few hours or so when it attempts to "sync with system clock" as I believe the BIOS internal clock is behind/wrong.

I also get BSODs like NMI_HARDWARE_FAILURE and KMODE_EXCEPTION_NOT_HANDLED.

I have run Memtest for 8+ passes and found nothing and I have attempted to update all my drivers to the latest versions... I'm just really lost on what the issue is.

My rig:

i5-2500k at stock
6GB unmarked ram (3x2GB)
Asrock z77 pro3
GTX 560 2GB
650W PSU
Xonar DG Sound Card