The ASUS ROG Xpander should soon be available. Designed exclusively for the Rampage III Extreme motherboard, this large daughter board plugs into the Rampage’s 2 PCI-Express x16 slots so as to give 4-way SLI support. NVIDIA demands 2 NF200 bridge chips on the motherboard as a condition for such a license, which entails an extra cost of $100.
Rather than bringing out a specific motherboard for what will be a very limited clientele, as Gigabyte did with the GA-X58-UD9 or EVGA with the X58 Classified, ASUS has found this original solution. The ROG Xpander will then connect to the 32 PCI-Express lanes available on the X58 Express and convert them to 64 lanes via the NF200s. A rather theoretical benefit as the practical advantage of an NF200 with 2 x16 ports but linked as x16 to the chipset has never been obvious compared to 2 x8 ports directly linked to the chipset. However as NVIDIA isn’t giving that option …
Note that for power, the ROG Xpander has a 6-pin PCI-E socket as well as three 4-pin Molexes, to power the NF200s (12W each) as well as the graphics cards which can draw up to 75W each via the PCI-Express port, or 300W in total when everything is only plugged in to 2 slots on the motherboard (150W maximum).
Note also that the ROG Xpander of course raises the graphics cards up in the casing and can therefore only be used in bench table set-ups.