My T-bird 750 is doing 950Mhz right now with an Alpha PAL6035. I am typing this and running SETI in the background. It will do 980 Mhz, but I can't run SETI there. You should be able to hit 900 easy with a good heatsink. I think my next CPU will be a 900 though. I can taste that 1000 Mhz.