i forgot to comment on another of operaguys earlier comments, using a single cpu on a dual motherboard is as simple as having a single processor acpi installed on your operating system. whenever you get the second cpu, you can just plug it in, the motherboard will recognize it instantly when you boot up again, and then in windows change your driver to a multiprocessor acpi and windows will begin to use it. Windows XP and Windows 2k use the same kernel when using cpu resources, neither has a performance advantage over the other as far as the processor goes.