I own a XPS700 system in stock version, means no motherboard change has been done!Currently equiped with a Core 2 Extreme X6800 (Core 2 Duo Extreme Edition)
From several sources I know now that its possible to run an Intel Core 2 Quad Extreme QX6800 CPU (see links), but I wonder whats about the QX6850 CPU? Just 70Mhz more than the 6800 but a FSB of 333MHz instead of 266MHz..
Re: DELL XPS 700 and a Intel Core 2 Extreme QX6850
I just bought a QX6850 and I have the same system like yours except for the CPU I have Q6700. And my computer won't start with the QX6850 now either the CPU is already dead since I bought a used CPU or its not compatible with this motherboard.