Bummer. On one of my computers this program crashed, lost the data and started over at zero after ciphering it's way up to 70%. It just finished the new WU though and seems to be stable now. It's an AMD 1.8g/256 RAM XP sp2.
Aside from this one I have installed this on my laptop, Hyper-threaded(50% cpu max) 2.8g/512 XP sp2 that is shut down at bedtime and a 3.2g/1m XP sp2 that only runs a few hours per day. I have several other machines (8) but I don't think they will be fast enough for this. 33mhz-533mhz.
Thanks for the link to this Dizzutch, I hope others will join in the fun.