The currently available SLI cards are cards based upon NVIDIA's 6800 Ultra, 6800GT, 6800 and the 6600GT cards. NVIDIA has 3 methods of SLI; AFR, SFR, and a compatibility mode. AFR stands for Alternate Frame Rendering. In this mode each graphics card renders a succeeding frame. In other words graphics card 1 will render frame #1, graphics card #2 will render frame #2 and so on and so forth. SFR stands for Split Frame Rendering. SFR divides the work on each frame to be rendered between the two graphics chips. In order for SLI to work, however, there needs to be two video cards.
Gigabyte decided to introduce their SLI board solution, the GA-K8NXP-SLI board at nearly the same time as NVIDIA introduced their nForce4 SLI chipset. The GA-K8N-SLI supports SLIing two compatible NVIDIA video cards. But what's really interesting about Gigabyte's solution is that they also decided to do something special with their SLI 6600GTs, and that is where the 3D1 comes in. I'll discuss this a little more in the installation portion of my review.
The 3D1 combines two 6600GT cores on a single PCB (Printed Circuit Board). This is similar in concept to the Voodoo 5 5500 from 3dfx, the ATI Rage Fury Maxx card from 1999, the Volari V8 Duo card from XGI and other solutions, which I may have forgotten. Instead of the solution taking both PCI Express X16 slots as most other nForce4 SLI solutions do, the 3D1 takes up a single slot on the board.
