Here's some more info about AMD's 4x4 platform which will be released on November 14th.
Here is the answer to a big question which has bothered many of our readers. Although 4x4 uses the Opteron processor socket "F", it will not use registered ECC memory. Athlon 64 FX-70/72/74 will ask for regular DDR2 memory modules, with Corsair, Geil and OCZ offering blazingly fast memory for the system. Corsair will get some preference in reviews due to the fact that it sports the so-called "Enhanced Performance Profile", also known as SLI Memory. This was co-developed by Corsair and Nvidia. However, there are now over five different memory manufacturers offering a combined total of 17 different memory kits.
Secondly, it will not only support quad-core Barcelona CPUs, but will support four graphics cards at the same time.