PlunX, damn dude, that bites royally! This Duron 800 I have here is @ 1-Gig, holding steady @ 39C, 45 under Q3 demoloop+RC5 loop, @ 1.75v
I have a K7T Pro2a + FOP32, so it seems our systems are similar. You have an "AMD-approved" power supply, right? 300-watt isn't necessarily enough, as they can be inconsistent in their output, which can muck up a good overclock.