Well, something is definitely bad in the system.

This morning Windows was stuck in a restart loop. After running last night for a good 6 hours without any visible issues.

When I did the memtest today at 9am it was coming up solid failures. We're talking thousands of failures by the time it got even part way through test #4.

I turned off the power supply, waited about 2 seconds and turned it back on. Still lots of failures, but noticeably less.

Turned off the supply again and unseated and reseated the RAM modules. This time only a handful (10) failures by the time it finished test #4.

WTF? Neither of the shutdowns waited long enough for anything to cool down. The only thing I can think of is that with a quick shut down there's still data in the memory that isn't getting cleared. But I still don't know whether to blame the RAM or the motherboard.

And here I find myself with one of the pitfalls of building my own system. Which item do I return? If this were a Dell or Apple, I'd just swap the whole system with the vendor, probably the same day.

Should I just go ahead and RMA the memory and mobo each on their own? I wonder how long this is going to take - the memory is Crucial and the mobo, as mentioned before, ASUS.

I'm past the 90 days of warranty offered by the store for the mobo, so now I have to deal with ASUS directly. For the memory I think the store offers service for 1 year - Crucial's warranty is lifetime I believe.