nVidia may have just launched 3-way SLI, but apparently the company isn't content with only one new product, if that is the right word for SLI. Anyhow, the pertinent issue here is that another is being launched, and this one is arguably the more important for the vast majority. To compete with Intel's P35, X38 and forthcoming X48 and AMD's 790 FX chipsets, nVidia has announced the nForce 780i SLI chipset for Intel processors - sorry AMD fans, you're still stuck with nForce 5 for now.
Unsurprisingly nForce 780i is compatible with 3-way SLI and nVidia's Enthusiast System Architecture which should enable tech-savvy users to tweak their systems to their heart's content. Intel's latest Penryn processors are, as mentioned, also supported although currently only those on a 1,333MHz front side bus, not 1,600MHz chips. Of course, the only one falling into the latter category is the QX9770, which isn't actually available to buy until next year, conveniently the same time as nVidia says BIOS update will be out to officially support the faster bus speeds.
Standard memory support remains in the realms of either 533 MHz, 667MHz or 800MHz DDR2, although up to 1,200MHz memory is supported using SLI Memory modules, and up to 8GB of the stuff can be used. This is probably the right decision because as much as DDR3 is likely to be the RAM of choice moving forwards, it's still too expensive for most and doesn't offer any particular performance gains; moreover, Nehalem is slated for launch in around a years time, so motherboards upgrades are going to be required soon-ish anyway. Back to the today, though, if you want the best possibly graphics performance (i.e. 3-way SLI) coupled with the best processor (sorry Phenom) then you'll need nForce 780i.