AK32A CPU speed

I just built a new machine. While troubleshooting an error code
I cleared the cmos w/ the jumper pin.

Before I cleared the cmos the AMD 2000+ was running at 1666mhz.
After I cleared the cmos the speed dropped down to 1250mhz.

Any advice on how to get back to the 1666mhz par would be greatly
appreciated. The cpu temp was 40C.

TIA

Henry