Im sitting here at work and decided that I would post something here to see if anyone has had similar issues and what the problem was. I have a new Core i7 920 in an ASUS motherboard with 6gigs of DDR3 1600. At first everything was fine. Then the computer would randomly crash. Its not the PS as in other build it works fine. Nor is it a graphic card issue as with other graphic cards, the problem persists. I figured it was either the memory or the MB. I had the MB tested and the lab said it was ok. I ran MEMTEST 3.5 with all three sticks and it LOCKED up after 15hrs. I took two out and it ran for 28 hrs with no problems or errors. I put in one more STICK and it ran fine for 40+ hours before suddenly rebooting and now thats all it does. It will load up to memtest and run for 5 seconds then reboot. Will bad memory cause a reboot in memtest? Or is this likely a motherboard issue?Yes.
1 or more of those 3 stiks are bad...
Run MemTest on them 1 at a time to find the culprit...If I have another computer that has DD3 1333 or 1066 (I cant remember) support, can I use the DDR3 1600 chips in it to test them on a different MB that is known to be just fine?

Also, can bad memory ever ruin a MB?, don't want this to happen.

RegardsOnly if the MBoard supports that speed...