thanks for the suggestions!
i ended up going with speedfan (though i haven't used sisoft sandra for temperature readings, i've read it's not that accurate?)...oddly enough i can't reproduce the problems i was having yesterday.
I just setup my system, and the first time around i put a very light coating of AS3 on my xp2000's core, and the idle temps were very high (~57C)...i took it out and slapped a bit more AS3 on, and my idle dropped to 44C. However, under max load, the system kept rebooting...i dunno if the AS3 needed to break-in, or my new Antec 430W truepower PS couldn't handle powering 3hd's, 3 cdroms, and 6 80mm antec trilight fans.
Anyway, 10mins of being under full load and i'm still here and hitting 51C 🙂