Sam, I have a Slot-1 Soyo board and I seem to get what I would call "accurate" readings. Note...when you have a Slot 1 Soyo board, the temp reading is going to come from the internal temp. sensor which is actually inside the Processor package...So...chances are, as long as the monitoring software is good (which I've heard it is), you should have more accurate readings then someone using and external board or socket mounted sensor.
If you plan on using alternate software to monitor temps...ie...Motherboard Monitor, check your temps in your BIOS first...then adjust the software to match the BIOS temps. Hope this helps.