In your BIOS, make sure K8 Cool And Quiet is disabled if your cpu fan is pluged into the mobo. This will make the cpu fan spin at 100%.
Check for a newer BIOS.
The stock HSF for the 3800+ is not good enough for a duel core cpu. I suggest an aftermarket HSF.
My 3800+ with the stock HSF is running at 49/121 deg on a DFI RS482.