NVIDIA Linux SLI Primer
Onto the final area of hardware coverage, we have the actual graphics cards. Although the NVIDIA 1.0-8XXX cards do allow for some better hardware tolerance with the Windows display drivers, and initial support under Linux, the two GPUs must remain matched in order to run Scalable Link Interface. However, due to driver advancements it’s no longer needed that the cards be matched brands/models; meaning that you can run one graphics card from a particular brand and then the same GPU but distributed from an entirely different manufacturer. In addition, one of the cards can have a different memory capacity meaning one card could offer 128MB of video memory while the secondary card features twice the amount. Through the present GeForce 6600, 6800, and 7800 series there are presently over 100 different possibilities for certified NVIDIA graphics cards. Among these cards are the GeForce 6600 and 6600LE graphics cards, which support SLI; however, they don't use the SLI connector bridge. Of course, the just released GeForce 6800GS and 7800GTX 512 also support the use of SLI.