The case might look familiar from the outside, but the new $3,099 Dell Dimension 8400 represents the opening shot in Intel's wholesale overhaul of the desktop PC's core technology. Featuring Intel's new 925X Express (a.k.a Alderwood chipset), a 3.6EGHz Intel Pentium 4 560 processor, and the first PCI Express graphics card we've seen--the 256MB ATI Radeon X800 XT--the Dimension 8400 is essentially a showcase for the future of the PC.
You can upgrade to a maximum of an HD4850 or 9800GTX. After that your CPU will bottleneck everything, and it may already start to with those cards.
That's going a little far isn't it ? Not all D8400's came with a 3.6E.
The addition of a 7900 GTO was enough for me to dump my P4 3.0 Dimension 8400 for a C2D setup
I like the 350w/28a psu, but it's kind of aged at this point, I'd reccomend nothing more than a 4770 or 9800 GT Eco model.