Either one is way too high for a stable operating temperature. Think about a better cooler! That 70 C is the upper limit . . . that is self-destructsville. I don't ever like to get about 52 C. I'm running a 750 K7 at 800 and the CPU temp is a nice, cool,
37 C. (Same mobo . . . K7M with the P2T probe attached.)
BTW, am also running 800 MHz w/o upping the core voltage at all. Just set the FSB to 107.