In Speedfan? Thats just reading a sensor that is not there, these programmes do require a little setting up, they don't automatically address the right sensors.
Knowing the m/board brand / model number / revision would be helpful.
EDIT: Everest has monitoring capabilities if memory serves me correctly, that could be another avenue to explore. Also SiSoft Sandra though as far as I can recollect they have no OSD like MBM5