Some oddnesses from back in the day with CPU temps...
First there was the in socket, CPU backside sensor, which if fitted snug to the board, by design or indifferent assembly was really a board under the CPU temp sensor. Some were up in their leads at an angle so you had to push against them slightly to seat CPU, some were a kind of flexi sprung type... Now, at first, these read raw, but then there were complaints/criticism, so they put an offset in the BIOS code, so when the motherboard read at 30C the CPU might read at 40C, which was kinda guessing really, but you could do comparative temps, idle to load.
Then, on die temperature sensors came in on some CPUs and were not necessarily supported at all or well in the first while. Now there was a freak out, because of two things. One, manufacturers tended to specify a Tcase maximum, temperature of the outside of the CPU, and two, although reading from the die some board makers continued the 10C offset they'd used on the socket sensors.... so there was a period when ppl were freaking out. "OMG my CPU is 50C at idle, 80C load!!!" ... now eventually the offsets got massaged back to "believable" or at least numbers that users like the look of. I think there has been some expectation management going on, such that perceived "normal" temps are actually close to on die temp readings these days. However, I still see Tcase quoted rather than maximum die temperature.
So, plucking a system from a particular point in time, hard to tell whereabouts in that above continuum it was exactly, later BIOS updates should have fixed any glaring temp errors from early in the board's life, but you'll wanna check up on one of the long running tech forums like overclockers.com or anandtech or somewhere to see what was going on when the board was new.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
