Introduction

Who hasn't yet heard about the new buzz Quad SLI? Well for those who didn't, NVIDIA has pushed once again the limits and instead of running two video cards together in SLI mode, they can now run four graphics processors in SLI mode. Yeah you got that right, four graphics processors running together to provide blistering performance. Of course you will need a decent computer to feed it. So start saving up for a top notch processor, preferable a dual core and with the highest clock rate as possible. We guess an Intel Conroe would be just ideal as that one seems to beat all competition currently.

NVIDIA has taken advantage of their leading position when it comes to multi-GPU technology, which they have introduced quite successfully some years ago. This technology was launched as SLI, Scalable Link Interface to bundle the performance of two graphics cards. SLI is a high-performance technology that intelligently combines and scales graphics performance and visual quality by having multiple NVIDIA GPU's in a single system. The NVIDIA SLI technology can scale both geometry and fill rate performance for multiple GPU's.

Taking the acclaimed NVIDIA SLI technology to the next level, Quad SLI delivers the most extreme HD gaming experience available on the PC. Combining the power of four NVIDIA GeForce 7900 graphics processing units (GPU's) with an NVIDIA nForce4 SLI based motherboard in a single system; Quad SLI lets you run your favorite games at an unbelievably high resolution of 2560x1600 while maintaining silky smooth frame rates. In addition, support for a new 32x AntiAliasing mode and 16x Anisotropic Filtering enable stunning visuals.

To get Quad SLI on the road NVIDIA designed a special board which goes by the GX2 abbreviation. The first version of this Quad SLI implementation was shown by Dell some month ago with their Renegade system. The Dell XPS 600 Renegade system featured four GeForce 7800 GTX 512MB GPU's and four custom PCB's that had been attached together in pairs. To hold this giant quad PCB construction Dell used a mainboard based upon the nForce4 SLI X16 Intel edition.

GeForce 7900 GX2 Technology

Some months later we saw the introduction of NVIDIA 90nm refresh graphics cards based upon the G71 chip, which is actually an optimized die shrink of the G70 core released last year. Just some weeks ago NVIDIA launched the GeForce 7900 series and with that also came the announcement of Quad SLI for all customers. Since then we have seen that NVIDIA worked hard in getting the a dual-GPU card ready for production and so the GeForce 7900 GX2 was born. Currently the reference design should be with the main launch partners of NVIDIA for getting their products together.

The GeForce 7900 GX2 is build up out of two PCB's that are paired up together. So in essence you have a dual-GPU graphics card, based upon the GeForce 7900 core. However, only one of the PCB's has a PCI Express interface connection. The PCB used for each GPU is longer as well. This is necessary in order to house the additional circuitry NVIDIA adds to Quad SLI enabled cards. This added circuitry is comprised of an additional chip that is used to provide both GPU's on the card with a total of sixteen PCI Express lines.

Each GPU on the GeForce 7900 GX2 card is outfitted with a single slot aluminum heatsink, with the cooler that is very similar to what we saw on the recent GeForce 7800 GS. The heatsink itself though is a bit longer, with the cards fan located offset of the GPU in order to increase its effectiveness. The GeForce 7900 GX2 is set at 500MHz core and 1210MHz memory speed, which is just in between the GeForce 7900 GT and GTX speed settings.

When turning over the GeForce 7900 GX2 card, we get only at the back of the second board which comes with the PCI Express interface. The back has no cooling whatsoever, the only thing that catches the eye are the nearly circular holes. These are located where the fan is located at the other side. Due to having two boards packed together the air intake has to come from somewhere and via this way NVIDIA made sure enough airflow can be drawn towards the enclosed GPU.