I have a 32bit os. I originally had 1gb and then bought 2 more. My mobo sucks for overclocking, though I've had my e6600 up to 3.5 but it wasn't stable at all. My mobo has some serious vdroop on it, but I've vowed to do it again, or maybe buy a new mobo. I hate my sig, I've been thinking about deleting it for a while now.