I assume you are refering to a socket 478 3.2E. It really depends on the motherboard. I had a P4P800, and my 2.8E ran fine on it at 3.5ghz. I also have a Gigabyte 8IK1100 875 chipset motherboard, but it's got 2 revisions, revision 1 does not support prescotts, revision 2 does. Mine is revision 1, so it doesn't support prescotts. I would check the asus website, so see if the 865 board supports the prescott, or if only certain revisions of it do.