It shipped with a Q6600 and a locked bios so the FSB, Vcore, etc couldn't be changed.
The motherboard specs say that it supports 800/1066/1333 FSB, so if I put a Core 2 Duo with a 1333 FSB, will the Motherboard run it at the correct FSB or insist on treating it as if it were a Q6600 and keeping the FSB at 1066.
What I'm really asking is, will the locked OEM Bios recognize a different CPU than the one it shipped with and apply the right clocks?
This came up in a thread over at Anandtech with the same motherboard (Asus G33 iirc), a poster added a Q9550, it didn't need a BIOS update and ran with no problems. So a short answer is that it should work, but typical caveats about double checking at HPs forums and tech support would be a good idea.
*EDIT* it also applies to the Berkeley-GL8E series in HP