Beyond The Hype: What Is Quad SLI?
Quad SLI is exactly what its title implies: use of SLI technology among four graphics processors. The world got a taste of Quad SLI In January, when Dell announced the XPS Renegade 600 with a slick fire paint job and Nvidia's Quad SLI. The news from CES stated that "the XPS system is expected to be the first to support two new NVIDIA GeForce 7800 SLI graphics cards, which can link four graphics processors to speed up overall video performance or draw images with intense realism". Unfortunately, this has not been the case; the first Quad SLI systems we received came from Falcon Northwest and iBuyPower.
Other reports about Quad SLI stem from initial views at CES. Many saw each of the Nvidia cards hooked up to external power 150 W bricks, and the speculation was that Quad SLI cards would require over 600 W of power just for themselves, not taking into account all of the other power requirements for the rest of the system. This figure was derived from the maximum draw from the internal connections at 75 W a piece, plus the 150 W external sources (150 W x2 + 75 W x4 = 600 W). In practice, this is not the case at all; the Falcon Northwest Mach V system we received is powered by a 650 W power supply.
Recent speculation said that the cards would be running GeForce Go 7900 GTX graphics cores at or around full speed, to deal with power and cooling of full speed desktop cores. However, Derek Perez, Nvidia's Director of Public Relations, stated that this claim was "totally untrue" - Nvidia implemented desktop chips. While they operate at the same speeds as the GeForce Go 7900 GTX with the core at 500 MHz and the memory at 600 MHz - 1,200 MHz effective GDDR3 speed - they are not mobile chips. The adjustment to the Quad speeds made it possible to decrease the power draw and the cooling requirements.