Is that stock HSF? Under stress or normal? I worry about o/c'ing the thermal tape. I tried, but I couldn't stand it after a while. I stayed at 260FSB with stock and when I swapped the tape appeared rather crispified. That's the reason for concern. What are your memory timings? VCORE, VDIMM? Also, I ran 285 briefly just to show I could, but I wasn't stable at those speeds to Prime95. I didn't up anything at that point except VDIMM (I run 2.75V w/ auto CPU voltage = 1.582V). My timings are 2-3-3-7-8.
EDIT: I'm not sure about transferability of settings considering differences in PAT and MAM/Turbo settings. I stress test each o/c several ways. First, UT2K3 with everything turned on. It makes o/c'ing more fun

. Then, I'll run Prime95 with a number of other programs (probe to watch temps, control panel to watch CPU usage until I get to around 90%, ATI TV, WinAmp w/ Visuals playing mp3s, WMP playing a DiVx file, and I'll watch a DVD watching for any anomalies). The final tier, when I'm looking to stick with an o/c, is running Prime95 for 12hrs or more. If I survive all that, I consider myself stable.