Got a bit further today - we're starting to think that the board's memory/chipset timings (that are not adjustable) are set up too aggressively. I've had just about every DDR2 module we've got (between both bit and TR) in each of the three boards and we're getting the same kind of errors on all three.
In particular, I believe the drive strength is set up too aggressively, since many of the crashes/hard locks we're getting are replicating what happened on a completely different board (with Drive Strength-related stability problems) that we're going to tell you about tomorrow.
