My 2.8C, D1 stepping, is running at 3.5Ghz (250 FSB) at 1.45V. I've run it all the way to 3.6Ghz but backed down just to be safe. Stock HS is fine at full load (DVD ripping), but I had to run with case open to keep it cool. So I installed a Cooler Master Cu HS and closed the case 🙂 even at full load. BTW, the temp is 44c idle, 53c full load. Also my CPU has 30 caps on the underside.