Btw, the ArsTechnica article said that more than 2 way SLI is possible.
You need a code from Nvidia and an older bridge...but it IS doable.
/e
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Three-way SLI? You'll need a code for that
For even more performance, there's SLI. Those hoping that Nvidia's rapidly ageing SLI technology for linking two or more graphics card together would die out with Pascal will be disappointed—but, on the flip side, at least there are a few improvements.
For starters there's a new jaunty, high-bandwidth SLI bridge—or rather, there are three of them, depending on your motherboard spacing. They are designed to link just two GTX 1080s together at a higher 650MHz speed (versus 400MHz) by using the second SLI connector traditionally reserved for three- or four-way SLI configurations. Nvidia claims that the new bridge results in less stuttering, although without a bridge or second 1080 to test, we'll just have to take Nvidia's word for it for now.
An odd side effect of the move is that, for the first time, Nvidia is officially recommending users go with a two-way SLI configuration, and those running 4K or monitor surround should use a HB Bridge. SLI has never scaled all that well past two cards—and four-card solutions are pretty much just for show in games—so this isn't all that surprising.
Enlarge / If you want to do anything more than two-way SLI, you'll need an unlock code from Nvidia.
What is is surprising, however, is that by default, anything other than two-way SLI, or two-way SLI with an additional card for physics processing, is locked out by the hardware. DirectX 12 games that support "multi display adaptor," where any number of mixed GPUs are controlled by the game directly, will still work, but anything involving SLI with more than two cards under Nvidia's driver is locked out.
There is a way around the lockout, although it is a little convoluted. Aside from having to use older, slower bridges, users will also have to download an app from Nvidia's website that generates a signature for their GPUs. That signature is then used to request a (free) enthusiast key from Nvidia, which users can then download to unlock the three- or four-way SLI function.
Quite why enthusiasts will have to go through that process is something of a mystery. After all, it's hardly like most regular users are going to schlep down the shops to buy a bunch of £600 graphics cards without knowing what they've let themselves in for.
This post was edited by Ghot on May 17 2016 07:58am