Nvidia announces 3-way SLI

Posted at: 3:55am 13th December 2007 by Ben Hardwidge

New triple GPU graphics technology works with existing nForce 680i boards, and plans to take on ATI’s CrossFire X

Nvidia has quite rightly been pretty sheepish about the whole Quad SLI thing since its shameful release back in mid-2006, but the confusing acronym specialist reckons it might have got the whole multiple GPU thing right this time, using three cards rather than four. If you’ve been wondering what exactly that third PCI-E graphics slot on your nForce 680i board was supposed to be used for (not to mention the second SLI connector on your GeForce 8800 GTX), then now you know; it’s for 3-way SLI.

Unfortunately, you can’t just use any graphics card for 3-way SLI, though. Even though Nvidia has just released the new GeForce 8800 GT and 512MB GeForce 8800 GTS, neither of these cards will work in triple SLI configuration. You’ll either need a GeForce 8800 GTX or an Ultra for Triple SLI, which means you’ll also need a healthy inheritance, or a dodgy credit company, in order to get hold of a 3-way SLI setup.

Not only that, but you’ll also need a beast of a power supply; Nvidia recommends a 1.1KW unit for 3-way SLI, and you’ll need to bear in mind that you’ll also need six PCI-E connectors for the three graphics cards too. Of course, Nvidia has also introduced a new connector for the job as well, which features six connectors and allows all three cards to share data with each other.

Interestingly, the 3-way SLI driver is currently only available for Windows Vista, which could well be because Nvidia has been working with Microsoft to increase the number of frames cued up for alternate frame rendering. The number of buffered frames was apparently limited to three in Windows XP, but has now been increased to four in Windows Vista after Nvidia and Microsoft’s efforts, and this is when using both DirectX 9 and 10 as well. However, Nvidia also promises that you’ll be able to change the rendering modes in game profiles, as you can with current SLI setups.

Of course, this is all completely useless unless you have decent game support, but Nvidia claims that 70 applications will be supported from today, and also says that it’s given 15 developers ready-built 3-way SLI systems so that they can make sure games work on them. Nvidia tells us that a patch for Crysis is also on the way, which will improve performance. Will this mean you can finally get a smooth frame rate with a minimum of 25fps at Very High settings? You should bloody well hope so, really.

You may remember that the third PCI-E slot on nForce 680i boards was originally rumoured to support a third graphics card for physics acceleration in the future, although this seems unlikely to happen now. Given that the guys at Havok are no longer speaking to ATI, we can’t imagine they’re particularly chatty with Nvidia either.

So how does it perform? We’ll have to wait and see, but you hopefully won’t be waiting long. Nvidia and POV have promised to send us three GeForce 8800 Ultra cards for testing 3-way SLI, and we’ll bring you the benchmark results as soon as we have them. Watch this space.