Look at the thread in dell benchmarks. Achilles supposedly has a X7900 and since he doesn't mention that it doesn't OC I assume it does. I do recall when the machine first came out there was a thread where I tried to assist someone to get the X7900 to OC in it and was unsuccessful. Maybe they released a new BIOS after that.
The reason I'm asking is I'm contemplating an Outlet buy. I'm either waiting for an M1710 with a T7600G chip to come along again...a rarity, I know, or M6300s to start showing up with 3600M Quadro cards instead of the 1600Ms. Seeing as a few of the M6300s have X9000 chips in them, I was curious.
Good, now I just have to wait for them to start coming into the SBA Outlet with 3600Ms.
Quite frankly I don't much like the idea of twin 8800GTX chips in a laptop chassis with the heat issues I'm getting with my original now three year old Gen 2. I like being able to use new drivers and not have to wait for "SLI-approved" ones. =/