Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm............weirdness.
You should let it run for an hour or 2 though, let it do a couple passes to fully test out the RAM just to make sure, but generally if the RAM was insanely bad I'd just error right off the bat.
Anyway...........I'm kinda gettin stumped now unless you did some major hardware change without formatting your hard drive.