With a bios flash and some luck I can push the cpu's to at least 2.5, I can't actually oc the cpu's, but I can use an ancient version of ntune to increase the HyperTransport clock of the mobo (see
this), which raises the core clock and memory clock. I can't do any voltage bumps either.
To clarify, I haven't bought any video cards yet and this system has four quadcore processors.