On 11/12/10 10:46 AM, Keith Roberts wrote: > > I have a sneaking suspicion that it's the mismatched low and > high density memory modules that are the problem? that sounds quite likely. some of those modules have two banks on the single module, and I seriously doubt a system is going to like a single bank and a dual bank module in a dual channel environment. I got in the habit a long time ago of *always* using matched memory modules.