When you boot, go into your bios and you can check your system health or whatever it's called....when you do this, it will give you a realtime reading of what your temp is.  If the system is cold when you start it, you will know if the reading is accurate or not.  It doesn't take long to heat up, but it's a processor, not a steam iron so if it heats to something TOO excessive(like over 41C, you'll know).  I have a PIII 800 on that board and it runs pretty constant at 39C.