Introduction

GeForce 6800 GT SLI up and running

6600 GT SLI system

S-L-I. These three letters are still dear in the hearts of many 3dfx Voodoo2 owners. The premise behind the technology is simple: take two Voodoo2 graphics cards, connect them together, and get double the performance.

SLI technology appealed to both the hardcore and mainstream user alike. Enthusiasts who had the cash would simply drop in both Voodoo2 cards and enjoy the benefits right away, which not only included performance, but one new screen resolution as well: 1024x768. Voodoo2 gamers on a budget ended up buying one card immediately, and bought the second card at a later date, typically 6-12 months after the original card purchase. After all, keep in mind that these were $300 graphics cards at the time Voodoo2 was originally released.

No other card manufacturer had an immediate answer for SLI. Not NVIDIA, not Rendition, nor ATI or S3, both of whom were rather late to the 3D game, despite their dominant positions in 2D graphics. Eventually ATI released their MAXX technology to the market, but this didn’t provide the incremental upgrade option 3dfx’s SLI solution offered gamers on a budget, as both graphics cores were integrated on the same card. The performance of ATI’s Rage Fury MAXX card was also nothing to write home about. Metabyte also made an attempt with their Parallel Graphics Configuration technology (unofficially nicknamed Stepsister), but unfortunately for Metabyte, by the time PGC was ready for public consumption, newer AGP graphics cards were released, no one was interested in high-end PCI graphics cards anymore. PGC was also never entirely effective at load-balancing: the top segment of the screen isn’t always as complex as the lower half. PGC never truly addressed this. Alienware eventually bought the technology from Metabyte but a final product based on the technology was never released.

One fundamental problem seemed to doom all of these early attempts to recreate 3dfx SLI: the AGP interface was simply never designed to handle dual graphics cards.

Another shot of the 6600 GT SLI system

Close-up shot of dual 6800 GTs

PCI Express however has been designed with dual graphics cards in mind. NVIDIA – who bought many of 3dfx’s technology and assets a few years ago – is the first manufacturer to bring back dual graphics cards; and the name they chose to market their technology is none other than the legend that started it all: SLI!