Yes it does; this card has built in SLI chip.
That's the biggest selling point.
It brings all the benefits of traditional SLI to non-nForce chipsets (and without any of the trade-offs required for traditional SLI, aside from the nForce chipset tax and traps):
1. Price - 680i SLI motherboards cost $100 more, on average, than their P3x/X3x Intel-chipset counterparts; the price differential jumps to $200 when you substitute 790i SLI. (Also, if you bring in G3x Intel chipsets, or even AMD-based IGP chipsets, most of which also include at least a single PCIe x16 slot, the differences only widen in terms of price.)
2. Stability - Kyle has commented rather long and hard on this issue, both in the reviews and here in the forums. Stability of Intel chipsets has continued to exceed that of nForce chipsets, even with the introduction of 790i.
3. Slot loss - Traditional SLI (and CrossFire also) both cause losses in slot availability due to both overhang and cooling requirements inherent in running two GPUs in two slots. Both the 3870X2 and 9800GX2 obviate this by being single-card solutions; however, the GX2 not only has higher performance, but is actually easier on the electric bill under load than the X2. The increased up-front cost for the GX2 vs. the 3870X2 can actually be made back in terms of electricity savings in less than two years. And there is the fact that you can use those slots that you normally wouldn't have available due to traditional SLI/CrossFire for things like sound cards, TV tuners, et. alia.
Sounds like the 9800GX2 is one heck of an *investment*.