[quiet mike]

Right now AMD has 2 tipes of 64 chips; the 940 pin Opteron (servers) and entusiast market FX version of it using buffered RAM and Dual Channel, and the 975 pin or something like that. This one is a little faster and allows for the much more cummon and sligthly faster unbuffered RAM, but with only half the L2 cahe and no Dual Channel.
Now AMD is moving both of these chips to a new 939 pin version that allows for buffered or unbuffered RAM and supports Dual Channel on any RAM. (AMD bus controller is on CPU not on motherboard, so here is a chip design not motherboard, like I was explaining on Dual Channel coment)

Yes, ATI will make the older versions native on PCI Express as well as the new versions. They are not out yet, but will be soon. nVidia said that for the moment it will use a bridge controller instead of a native chip. We don't know if that will trully impact performance or not. Well have to see once they can test a full PCI Express package.

Happy buying~!