Hi Aaron,According to this review of your mobo :
http://www.ocworkbench.com/2003/asrock/k7s8xe/k7s8xegallery3.htm
It says :
There are two jumpers for selecting the default FSB of 100, 133,166,200
Also :
The CPU Host Frequency can be set to AUTO (based on jumpers on board) or set Manually. In Manual mode, the FSB can be set from 100~248 at 1MHz stepping.
So I would suspect that you have the jumpers set for the wrong FSB and then also set at AUTO.
Check your manual for the relevant jumpers and their settings and I think you will be able to run at max speed once you have reset them :doggie: