Here's a weird one because it has plagued not only my current build but also my previous rig...
Sometimes only the slightest bump on the side of the case will cause the computer to lock up. Everything is seated and solid. I even often even haul the computer around to show people the innards while it's running and it never freezes. But just give it one...little...quick pop of a nudge while walking by (or riding by in my case...wheelchair) and it's lock city. It used to happen on my previous machine as well. The only common software related issue I can think of is that both computers may be (MAY be!) under a particularly heavy load at the time. Either from a game or by heavy multitasking. The only hardware similarities have been the use of Corsair Dominator RAM and Western Digital Velociraptor hard drives. (different units of the same class of parts in both machines) I also run a mild overclock and did on the previous machine. The only thing I can think of is that maybe a bump might cause a mechanical drive to skip a beat. But the nudges that cause the locks seem so very slight! Could it just be happening right when a machine might be susceptible to sudden velocity changes? Like a drive is trying to access just as a quick tap to the chin comes in with a left hook? Maybe the Vraptors are touchy beasts and should all be destroyed? Clever girls...
OS - Windows 8 Pro
Mainboard - ASUS P9X79 DELUXE LGA 2011 Intel X79
Processor - Intel Core i7-3820 Sandy Bridge-E 3.6GHz
Memory - CORSAIR DOMINATOR GT 32GB (4 x 8GB) DDR3 1866 (PC3 15000)
Video - EVGA 04G-P4-2686-KR GeForce GTX 680 4GB
Audio - Currently Onboard (come on Creative Labs Sound Blaster ZxR! woohoo!)
System Drive - (2) in RAID0 OCZ Vertex 4 VTX4-25SAT3-256G 2.5" 256GB SATA III (SSD)
Data Drive - (2) in RAID0 Western Digital WD VelociRaptor WD1000DHTZ 1TB
Optical Drive - LG WH14NS40
Cooling - CORSAIR Hydro Series H100 (CWCH100) Liquid CPU Cooler
Power - CORSAIR HX Series HX1050 1050W