Using a not compatible component on the motherboard does not necessarily mean that it will not work since the first time that you test it on the system. However, even if it works for a long time, the system is more susceptible to fail in a near future.
"Processors not specifically listed by type and rated speed may have requirements that are not supported by the desktop board's design. Use of unsupported processors may result in improper operation, damage to the desktop board or processor, or reduced product life."
Furthermore, please keep in mind that using any product out of the specifications, voids the warranty of it.
You can use a Xeon on it? LOL. This board is some piece of work, really. Try installing Windows on it with an external graphics card or booting into DOS with the latest BIOS - need I go on?
BTW, I don't think that this board is really suited for a 65nm Quad. Those bad boys run way to hot and consume way too much power for a puny 3-phase VRM of this board. I'd fully expect some capacitor to just blow up under stress with a 65nm Quad. Heck, I saw an Asus P5K-VM (3-phase) blow up with a Q6600, and that was definately a tougher board. I went with a Q9400 with my DQ45CB and something tells me this board isn't beef enough to run even a full-blown 12MB cache Quad - those things get too hot, coolers get noisy etc. Not my cup of tea.