Introduction

One feature both ATI and NVIDIA are touting with their latest GPUs is the ability to game at extremely high screen resolutions with very playable frame rates. 1600x1200, long considered to be a challenging resolution for even the most expensive GPUs, isn’t enough, we’re talking screen resolutions as high as 2048x1536 and 2560x1600.

At resolutions this high even a mighty GPU like the GeForce 7900 GTX will begin to chug in certain situations in some games, particularly once anti-aliasing is turned on. This is where NVIDIA’s SLI technology comes in.

With SLI, a second graphics card is added to the system, splitting the graphics rendering workload between both graphics cards for improved performance.

GeForce 7900 GX2 and 7900 GTX 512MB (bottom)

Dual GeForce 7900 GX2 cards for Quad SLI

While it’s only been on the market for about a year now, NVIDIA’s SLI technology has gained considerable traction, NVIDIA’s sold well over a million nForce4 SLI motherboards to the public – despite their higher price tag – and most games on the market have out-of-the-box support for the technology.

Size comparison -- big difference!

Quad SLI up and running in the ABS system

But with the latest games using 3.0 pixel and vertex shaders more extensively, and HDR lighting and other eye candy features like volumetric effects and soft shadows being used more often, even two GeForce cards running in SLI may not be enough. To tackle this challenge, NVIDIA has developed Quad SLI, combining four graphics cards together to theoretically deliver four times the performance of one graphics card. But does Quad SLI really deliver twice the performance of a conventional SLI system? That’s the million dollar question everyone’s wanted to know since Quad SLI was first demonstrated to the public by NVIDIA and Dell at the Consumer Electronics Show at the beginning of this year.

Cards are connected for Quad SLI

Note the PCI-E power connections

In case you don’t recall, Dell and NVIDIA made a huge splash at CES, showing off Dell’s Renegade XPS 600 PC, a 4.26GHz Pentium D Extreme Edition rig tricked out with four GeForce 7800 GTX 512MB GPUs and a custom paint job. In our Quad SLI: Demystifying the Rumors article we explained how the technology works, what components you’ll need to get a Quad SLI system up and running yourself (as well as clarifying what components aren’t compatible with the tech), and also discussed the supply and availability questions that were brought up in the months following Quad SLI’s debut. The short answer is that Quad SLI is compatible with all nForce4 SLI X16 motherboards, both AMD and Intel-based, but if you want to get your hands on Quad SLI, you’ll have to buy a system from ABS, Alienware, Dell, or one of the other 20+ PC manufacturers NVIDIA lists on their Quad SLI website. For now standalone cards aren’t being sold to the retail market.