Upgraded my little old Shuttle XPC-SK41G from an AMD Duron 1.3ghz to an XP 2600+ and couldnt get the speed up above 1150mhz after much digging about realised that the FSB is set to 100mhz by a jumper,
it is jumper JP2, you need to remove it and the FSB then runs at 133mhz and got a speed of 1536mhz out of the new chip. The jumper is located at the rear left, mine had a red jumper on it !!
Shame these old shuttles dont have 333mhz FSB then would get even more speed out of them ah well, when I completely upgrade the PC….