Yeah, mine is barely stable at 1.75 volts at 2.4 GHz, so you will probably need more. I have seen others giving it only 1.65 and running just fine at 2.4, but these P4s all seem to be different. You will probably have to do the wire trick to up the voltage more, but I don't know anything about that. The temp thing has something to do with your board, most of those boards don't have working temp modules or maybe its just a bios thing that they will fix later, but it seems to be common.
Jonny