I have an XP90 (not even as good as the ultima) on my X3350 (runs cooler than a Q6600), and @3.5 under full load, it does 71c, so I would say you are in the ballpark.... I tried a Q6600 a while back on my XP90, and it was doing 74-77 @ 3510, so again, I think it may be all that cooler can do.