The graphics community was abuzz yesterday with the news that nVidia is bringing dual-card gaming back to the PC. The technology, known as Scan Line Interleave (SLI) was first pioneered by 3Dfx, the company that nVidia swallowed whole in 2000.
Long time graphics fans will remember the power of the 3Dfx Voodoo 2 card with reverence. It was a great performer on its own but when combined with a second Voodoo 2 card in SLI mode – it was extraordinary.
The announcement steals much of thunder away from Alienware, whose own Video Array solution is patent pending. However, Alienware’s Video Array has the advantage of also working with ATi cards.
SLI died a death on the PC as it required two graphics cards , while the AGP specification only supported one slot. ATi did rekindle the idea with its Rage Fury Maxx, which incorporated two graphics processors on one board, but this was no more than a short lived kludge that enabled ATi to compete with nVidia’s GeForce which was ruling the roost at the time. While 3Dfx also tried the technology once more with the Voodoo 5500, but it made little impact on the market at the time.
Now with the emergence of PCI Express, SLI is once again in contention. The announcement of SLI explains the pin connectors present at the top of the GeForce 6800 GT PCI Express card we've got in our Labs - look out for a review of that card soon.
Lucky owners of two PCI Express GeForce 6800 cards will be able to use this connector to pair them by means of what is cunningly being called the 'nVidia SLI connector'. nVidia has designed its new GPU’s so that they can communicate with each other, with software algorithms enabling the work to be shared efficiently between them.
The SLI connector is visible just above the fan
The technology obviously requires a motherboard with two x16 PCI Express slots – which so far will only be found on the new Xeon ‘Tumwater’ E7525 motherboards, coincidentally announced yesterday.
One can speculate that since SLI is an nVidia technology it will bring out a new version of its nForce chipset to make support available at a lower cost than high-end Xeon boards. This would also open the market to AMD CPU owners.
The welcome re-emergence of SLI indicates that the legacy of 3Dfx is still having an influence inside nVidia. With the announcement it certainly looks as though the Californian company is prepared to go to extreme lengths to regain the performance crown that was for some time possessed by ATi.
We spoke to ATI to see if it had a response to nVidia’s announcement. Its spokesman was not surprisingly tight-lipped stating that ATI wouldn’t comment on unannounced products, though he did hint that we could expect an announcement on ‘performance products’ in the new few weeks. We await it with baited breath…
Meanwhile, for the moment it certainly looks like it's advantage nVidia, assuming you have very deep pockets of course.