Readings in IS7 bios varies...

Is this normal for these boards for the cpu fan and the nb fan speed readings in the bios to jump around?
The nb fan reading especially. I've been watching it in the bios and it bouces from 0 to 21,000 something sometimes..
The cpu fan reading from 0 to 5625, where it should be.. It's a brand new tornado from Vantec.
It is plugged into its own molex from the ps..


Anyone have any ideas or is the board messed up?

Yeah my NB fan is going from 2000-10000 rpm. Usually around 7000 it stays. No problems yet so I dont care, im pretty sure its just a buggy sensor.