I would think that if this be a real celeron D processor, chances are good that 800 fsb CPUs are also supported, as the launch date of the Celeron D was at the end of 2004, and the chipset would have to have prescott support as well to run the Celeron D, meaning a relatively modern socket 478 chipset. Nonetheless, if garyd45 would be kind enough to give us the model # of his eMachine, we could determine which CPUs it supports.