AMD Quad FX and NVIDIA’s Four Card SLI – Will it Work?

Four GeForce 7900 Graphics Cards and Quad FX

Now that the AMD Quad FX platform has been successfully benchmarked and overclocked, I can now have some fun with the system. With four x16 PCI Express slots present on the ASUS L1N64-SLI WS motherboard I figured why not populate all of them? At first I was going to use several NVIDIA GeForce 8 series graphics cards, but didn’t have enough 6-pin PCIe power headers and all the cards I have take up too many PCI slots. With NVIDIA and ATI soon moving over to systems that contain three graphics cards (two for graphics and one for physics) the market will soon have power supplies with six 6-pin PCIe headers. For now not even the $599.99 PC Power & Cooling 1KW power supply has six PCIe connectors. It just goes to show that no matter how much you spend that you’l never be future proof. Upcoming power supplies like the Thermaltake ToughPower 1000W and 1200W power supplies will have six connectors and will be ready for both ATI’s and NVIDIA’s three card gaming solutions.

Limited by the size of the cards and power headers I installed two XFX GeForce 7900GTX graphics cards and a pair of GeForce 7900GS graphics cards to occupy all the x16 PCI Express slots with the same series of video cards. I then fired up the AMD Quad FX test system and was shocked to see that when Windows XP loaded that an alert message poped up saying that the system was SLI Ready.

After clicking the alert the ‘SLI Configuration’ utility opened and showed that I could enable Quad SLI. It seems that the NVIDIA drivers correctly detected the two sets of graphics cards and was ready to enable true Quad SLI, which would make four graphics cards operate as one card. I of course clicked the enable box and hit apply.

After hitting apply I was prompted to restart the system for the settings to take effect. A popup also opened stating that the GPUs were not connected by a video link connector, but SLI would still work.