Last week, NVIDIA formally launched the dual-GPU powered GeForce 9800 GX2 graphics card and the nForce 790i SLI Ultra chipset. We evaluated both of the products in depth in our coverage of the launch, but had to leave out one important detail per NVIDIA's embargo agreement, being Quad SLI. It wasn't that Quad SLI needed some more time in the oven, however. In fact, we had the drivers in hand to do Quad SLI testing well before last week's launch. The delay in GeForce 9800 GX2 Quad SLI coverage was simply due to a timing issue and commitments NVIDIA had made with a few of their OEM customers, who will likely be announcing Quad SLI powered system sometime today. - HotHardware

ASUS Extreme N9800 GX2 Quad SLI Graphics Review

As its name suggests, Quad SLI consists of a quadruple GPU configuration. And while today's version of Quad SLI is new, it is not a brand new technology. As many of you probably know, NVIDIA had previously launched Quad SLI with the GeForce 7950 GX2 in mid-2006. Due to the timing of its arrival, GeForce 7 series Quad SLI was married to Windows XP as such. Ultimately, difficulties getting many games to scale led to diminished support from NVIDIA. With Windows Vista and its completely new driver model and a new version of DirectX right around the corner, however, it's clear why NVIDIA took some focus away of Quad SLI solution, as distasteful as it is as existing customers got left out in the cold.

A pair of ASUS Extreme N9800 GX2 cards running in a Quad SLI configuration showed increased performance in every application we tested versus a single GeForce 9800 GX2. Overall, performance was extremely good and in the majority of tests the Quad SLI configuration was the fastest of the bunch, occasionally by a large margin. This most recent incarnation of NVIDIA's Quad SLI technology is vastly superior to 2006's version. A single GeForce 9800 GX2 is fast, but a pair of them running in Quad SLI mode is extreme, albiet not for everyone. The main reason being quite costly and requiring a very fast computers as a whole.

Although we're certain Quad SLI won't scale in every game, it did scale with every application we threw at it today and its performance was top notch. And in the near term, we expect NVIDIA to further improve Quad SLI's performance scaling as well with upcoming driver releases. What the long term future holds remains to be seen, however because it is getting increasingly hard to leverage multi-GPU configurations with more advanced rendering techniques. Now Quad SLI with a pair of GeForce 9800 GX2 cards also consumes less power than the competition's quadruple GPU configuration, like the Radeon HD 3870 X2 card.

While idling AMD's implementation used less power, but once put under load, NVIDIA's Quad SLI was clearly more efficient. So not only was it faster, but it used less power. Of course, this kind of power comes at a price. A pair of GeForce 9800 GX2 cards will currently set you back a cool $1200, provided you've already got the necessary nForce chipset based platform to install them in. Cutting edge PC hardware has always been an expensive proposition, so we're sure none of you are surprised by this. We are impressed with GeForce 9800 GX2 Quad SLI and hope NVIDIA continues to improve the technology.