Where do you get this??? AMD's whole marketing angle for 4x4 is that you can
upgrade to oct!!!!
4x4 are Opterons not Athlon64s, they use socket 1207 not AM2. The 1207 is
the second Opteron socket, the Opteron has had only two sockets so far,
940 and 1207. The Athlon64 has had four sockets, 940 (same as the
Opteron), 754, 939 and now AM2 (which has 940 pins but it's a completely
different pinout then the original 940). The 4x4 is a consumer rebranding
of the the Opteron 2xx, it's two Opterons on the board each with two
cores, for a total four cores. It's not a four core chip. The true four
core chips are coming late this year. I would expect that the four core
Opterons will stick with socket 1207 because the Opteron is aimed at
servers and that market demands much more compatibility then the desktop
market so if you were to get a 4x4 board you would probably be able to
upgrade it to eight cores. However there is no guarantee that that the
socket AM2 boards will be upgradeable to four cores. There is no technical
reason why they couldn't use the same socket, it's just that AMD has had a
history of changing the socket every time they update their desktop
processor.