With SLI you can use 2 Nvidia 6x00 PCI-E cards to increase performance. THG has an article on the front page somewhere I think.
Having to buy 2 graphics cards makes it prohibitively expensive for most people, but it gives the option of getting one upper-mid level card (e.g. a 6600GT card) and then adding another one a lot later, when they've dropped in price.
Nforce4 will be the first PCI-Express chipset for the Athlon 64 system, so will be the first to offer SLI support. This is interesting because the A64 is a much better gaming processor than the P4.
"Sex without love is an empty experience...
But as empty experiences go, it's one of the best" - Woody Allen
Yup, you are absolutely right Ned_Flanders... sorry, I wasn't thinking when I posted it. I am now off to read the article, and if I still have questions, I'll post in the correct forum, sorry for wasting the space guys.