On that same subject of More than 2-way SLI.........
I Just saw This Post in the EVGA GeForce 900/TITAN X Series Forum about the Newest Nvidia GeForce Drivers (372.54) where it appears they have also evidently disabled 3 and 4-way SLI if you are using Hardware OLDER than the New Pascal Series!
Betelgeuse
Seems like 3-way and 4-way profiles have been removed, at least for the Witcher 3, from these drivers. Got terrible performance and saw that only 2 out of my 4 cards were being used, any changes or forcing all 4 cards to work resulted in terrible performance. Going back to older drivers fixed the issue. I hope they're not getting rid of multi-GPU support for older hardware too...
Now, THAT is hitting below the Belt!
If Nvidia is starting to disable 3 and 4-way profiles in their latest drivers for the New Pascal cards and the Older Hardware also, They really have become inflexible about anything over 2-way SLI profiles except for a very Few Benchmarking programs that allow 3 and 4-way SLI to work.
Thanks NVIDIA, You have managed to send me Back in Time to 2008 when I had nothing but Two EVGA 8800 GTS in 2-way SLI.