Hey, I have a PD 945 too!! And I'm getting a DS3 in a couple of weeks.
Is 254 the highest stable OC you got? And what about temperatures? Right now I have a TT Big Typhoon, and under load the cpu will break 70C!! (stock speeds) 8O I couldn't imagine OCing it very far because of heat.
I just upgraded from d805 to 945. I ran the 805 for about 6-7 months at 3.4GHz and ~75C folding 24/7. The processor never actually burned out, but it did start acting up and working unreliably. I'm running the 945 at 223x17 and keeping my temps reasonable this time, peaking around 56. Once the AS5 burns in, maybe I'll go higher. This is on an Asus P5WD2-E with a Zalman 9500LED in a room that doesn't get much above 70F. If you want to go balls out, tho, I've seen screenshots of this processor at 5+ on water cooling. Good luck