More info is needed. If it is a PowerMac then you can most likely pull that processor out and put a new one in. Otherwise your luck may not be so great. There are some upgrades for other computer, but the PowerMac is the easiest to upgrade. So if it is a PowerMac, probably yes. If not, then maybe. But I don't think that you can overclock the processor that is in it, but someone else might be able to provide a better answer here.