According to PCPerspective, NVIDIA will no longer require ‘enthusiast key’ for those who were planning 3 or 4-way SLI GTX 1080 configurations. However such systems will only work with selected applications.
NVIDIA GeForce GTX 1080/1070 3 & 4-way SLI only for synthetic benchmarks and selected games
Those who bought more than two Pascal-based graphics cards, may want to reconsider returning some of these cards, as NVIDIA has currently no plans to support anything beyond 2-way SLI configurations, at least the way they used it.
NVIDIA has changed its stance when it comes to so-called ‘enthusiast key’, which was meant to unlock 3,4-way SLI only for those who really need it. It is said that such key will no longer be required, and such configuration will be supported in future drivers. However, this will only work for few games and synthetic benchmarks.
In other words, it is strongly advised that you shouldn’t buy more than two Pascal cards for one system, if you are only going to play games, as there’s a good chance it won’t be supported anyway.
With the GeForce 10-series we’re investing heavily in 2-way SLI with our new High Bandwidth bridge (which doubles the SLI bandwidth for faster, smoother gaming at ultra-high resolutions and refresh rates) and NVIDIA Game Ready Driver SLI profiles. To ensure the best possible gaming experience on our GeForce 10-series GPUs, we’re focusing our efforts on 2-way SLI only and will continue to include 2-way SLI profiles in our Game Ready Drivers.
DX12 and NVIDIA VR Works SLI technology also allows developers to directly implement and control multi-GPU support within their games. If a developer chooses to use these technologies then their game will not need SLI profiles. Some developers may also decide to support more than 2 GPUs in their games. We continue to work with all developers creating games and VR applications that take advantage of 2 or more GPUs to make sure they’ll work great on GeForce 10-series GPUs.
For our overclocking community, our Game Ready Drivers will also include SLI profiles for 3- and 4-way configurations for specific OC applications only, including Fire Strike, Unigine and Catzilla.