I have that board, and that heatsink but I'm not using them together. I'm using a Zalman7000AlCu with that board and it works great.
Playing with the XP-120, it looks like there will be clearance issues with it's heatpipes. They look like they'll either impinge on the DIMM slots on one side or a row of caps on the other side, depending on which way you choose to orient the heatsink.
Are you trying to run this fanless? If so, I'd look at the XP-90. It's about 95% as good as the XP-120 with a whole lot less fitment issues.