I've run it on my PC and attached a pic for ya in slot #1 on my board I have a 256MB stick of PC2700, that is it can run at a FSB of 133 or 166 @ DDR so to upgrade this pc I would need a compatible stick of PC 2100 or PC2700 as Nails said a PC will run as fast as its slowest component. In effect that RAM is underclocked. I know its confusing but post what shows in there and we can see what ram it takes.
HTH