First Look: Nvidia 3-way SLI on nForce 680i

Nvidia’s 3-way SLI on nForce 680i

Manufacturer: Nvidia

The run up to Christmas has been an exceedingly busy time for both major vendors in the discrete graphics industry, and most would have expected Tuesday’s GeForce 8800 GTS 512 launch to be the last one before the break. Nvidia has other ideas though, as it is today announcing the release of a driver for Windows Vista that enables support for 3-way SLI on all nForce motherboards with three PCI-Express x16 slots.

Over the past couple of days, we were given access to the driver in order to get an idea of how well 3-way SLI is shaping up. Nvidia has been quite open by saying that 3-way SLI will be shown in its best possible light on its next-generation platform, whose launch isn’t too far away, but in the interests of giving its current customers an upgrade path, it has enabled 3-way SLI on all existing nForce 680i SLI motherboards.

Considering the fact that Intel’s 45nm processors will not function properly in any of the nForce 680i SLI motherboards available—something that Nvidia says was out of its control—it’s good to see that Nvidia is at least offering upgrades for existing customers where it can.

Before we go any further though, we need to get straight to the point on one thing: 3-way SLI is not for everyone – far from it in fact. The reason why is because 3-way SLI can only be enabled on graphics cards with two SLI fingers along the top edge of the card. As a result of this, there are only two cards that currently support this new multi-GPU mode and it will probably come as no surprise to learn that they are the GeForce 8800 Ultra and GeForce 8800 GTX graphics cards.


Even one GeForce 8800 GTX is out of most people’s reach at £285 a pop (never mind three GeForce 8800 Ultras) and once you factor in the cost of an ultra high-resolution monitor, you’ll understand why 3-way SLI isn’t for everyone. The graphics subsystem alone is going to cost you the best part of £900 if you were to buy three GeForce 8800 GTXs and then you can add at least another £850 on top of that for a 30-inch widescreen monitor.

SLI has been around for over three years now, as it was first introduced in October 2004 when the GeForce 6800 Ultra was the top dog in Nvidia’s product stack. Ever since then, SLI has proliferated into something of an ecosystem, with millions of SLI-ready GeForce 6, 7 and 8-series graphics cards shipped to customers.

The GPU isn’t the only thing that makes up the SLI ecosystem though, because there is also the all-important nForce chipset. Nvidia took a brave stance by preventing users from using SLI on other chipsets and, during our meetings with key people inside the company in October, the situation isn’t going to change. Nvidia told us that it will not open SLI up to other chipsets in markets that it competes in for a number of reasons.

The first being a fairly obvious on, in that it’s much easier to qualify and optimise both hardware and drivers if the engineers know exactly what configuration the customer will be using. The second reason is less obvious and certainly open to debate, as Nvidia believes that with nForce, it has the best and most feature rich platform available.

Anyone that has been following this industry for a while will know that this isn’t the first time that Nvidia has attempted to cram more than two GPUs into a system – oh no. The first time was, of course, Quad-SLI – it had a rather difficult birth (that’s probably putting it rather nicely) and although Nvidia made massive steps forward, it was still a solution that wasn’t worth investing into. In fact, Nvidia is yet to release a Quad-SLI driver for Windows Vista, over ten months since its release – we’re told that the driver “is coming”, but there is no firm date on when we can expect it yet.