PresenTech (Michael Phillips {99710})

With the launch of Intel's 900-series chipsets and the recent return of SLI to video cards, PCI Express has finally arrived on the PC enthusiast scene in a big way. PCI Express-enabled motherboards are going to start becoming more and more common, and with the new bus's increasing ubiquity will come the inevitable confusion that accompanies the rise of any new technology, especially one as complex and feature-rich as PCI Express.
Today, NVIDIA is announcing is new SLI technology for GeForce 6800 graphics cards with PCI Express. The "golden finger" protruding from the top of the GeForce 6800GT is, in fact, an SLI connector. Place a pair of GeForce 6800 cards into a special motherboard with a pair of PCI Express X16 expansion slots, and this connector will help hook the two cards together for tandem operation.
SLI technology began a year after 1996 with the introduction of the Voodooo2 Graphics card. Two cards could be combined using a type of SLI (Scan Line Interleave) configuration. The entrance of PCI-Express and NVIDIA re-introducing the SLI concept now called Scalable Link Interface will take over the Graphic Card market
Voodoo2 SLI utilized a ribbon cable connecting the two Voodoo2 cards internally and a pass through VGA cable externally to distribute the analog signal. However, NVIDIA's implementation is all done drawing on digital technology.

A SLI, Scalable Link Interface connects the two PCI-Express cards, named the MIO port, a high-speed digital interconnect which connects to a connector on top of both cards allowing them to communicate to each other and allocate the workload which is accelerated by dynamic load-balancing algorithms. NVIDIA has not released what makes their SLI implementation tick exactly (besides the fact that both hardware and software contribute to making SLI work), most of the dynamic load balancing between the two graphics processors is handled in software and thus SLI needs driver support, which are as of yet unreleased, to work. Exact performance figures are not yet available, but NVIDIA says that prospective performance numbers should show a performance increase closer to 90% over that of a single graphics card.
You need a motherboard that includes two PCI-Express x16 slots which will also use the more costly Intel Xeon processors. Secondly you'll need two identical, same brand and type, PCI-E GeForce 6800 graphics cards. This extreme hardware and software comes with an extreme price starting at the PCI-Express cards which come up to $500 US for one. Regardless of the price the capabilities are endless. More power (90% increase compared to one graphics card), larger bandwidth (60X more bandwidth), higher resolution (1600 x 1200 easily), and workstation capabilities (four monitors connected to one CPU) are just some of the features offered by SLI technology using PCI Express.
I believe that soon this card would become standard due to the demand for better graphic performance and the fact that the latest version of Windows operating system is going to be in three dimensions. NVIDA’s SLI technology along with the PCI-express graphics cards have propelled them to No.1 in terms of “The best 3D performance available” and have again revolutionize 3D graphics once you’re willing to pay the price.