So I decided to bite the bullet and try to upgrade my dual socket board. Got some 4mm washers (~1.8mm thick), the 2mm thermal pad, swapped in the first X5675, and system came up fine -- recognized memory in all 4 slots, thermal/fan worked on socket A. Socket B didn't go so great. Followed the same procedure, but video never comes up (whether or not I have ram in slots 5-8). I know the cpu actually worked in a single-socket board, though I guess I can't really tell if the QPI link actually works for either of the new CPU's. EDIT: No bong with both cpus ... I'm hesitant to over-tighten and break the board - I can tell there's a bit of a gap between the washers and the heatsinks, but that seems to be true on socket A as well. Any advice?