@psycho is right, enabling on-board video fixes it.Z87X-UD4Hi7-4770k4x8gb Mushkin 997110 (1600mhz 9-9-9 1.35v)With the i7's onboard video disabled and all four 8gb sticks in the board I got app crashes and BSOD's about every hour or two regardless of what timings or voltage I used. With onboard video enabled the crashes have gone away completely. Its 100% stable using the RAM's XMP profile with no additional BIOS changes.