Nvidia GTX 1080 SLI Support Comes Into Question
With the launch of the GTX 1080 and the following announcement of the high-speed SLI bridge many have come to question how many cards you will be supported in SLI.
As many of you know NVIDIA can control how many cards will be supported in SLI in two ways.
The first is at the hardware level with the number of SLI connector (or “Fingers" as I call it sometimes) located at the top of the card. If there is only one then you are only allowed to run 2-way SLI. (eg two physical cards). Cards that come with two SLI connectors can physically support 3-way and 4-way SLI.
The second control method is via the driver. This impacts cards with two SLI connectors and while most are unlocked allowing you to run 4-way configurations there have been situations where NVIDIA has limited card support. The most recent of these was the GTX 770 being limited to 3-way SLI even though the card could physically be linked in a 4-way configuration. Of course that doesn’t stop you from running four cards but one needed to be run outside of the SLI configuration.
A Third way is via the video card BIOS but, in the big picture that is easy to bypass
So how does this impact the GTX 1080?
Well, the high-speed SLI Bridge is designed for 2-way card configurations and uses both of the SLI connectors.
But wait? Don’t most enthusiasts use both connectors in 2-way card setups? Why yes, yes we do and it remains to be seen if that did anything back then, but now. It seems they are using both connectors to transfer more data between the GPUs and offer better SLI scaling.
When the rumor/”educated theory” broke many turned to the various forums looking for answers. Some YoubeTubbies denounced the rumor in favor of exciting video content “to follow” and pad their monthly views.
There was at least one official response from EVGA claiming that GTX 1080 was limited to 2-way SLI only. However, that comment has been pulled and replaced with “coming soon” message
So here is my take on the whole situation.
High-Speed SLI Bridge: Hey it uses both connectors and there is no way to lace up any more cards so using that bridge effectively means you are limited to 2-way SLI.
Driver Support: Yet to be seen but it is totally within the power of NVIDIA to limit SLI support and they have done it before. Given that 90% of SLI users only use 2-way SLI AND that 2-way SLI has always been the most efficient SLI configuration I can see the politics.
Personal Feelings on the Matter: It would be easy for NVIDIA to allow 3-way and 4-way SLI support on GTX 1080 and then give performance benefits to those who use the approved configuration. The 10% of users who rock 3-way and 4-way setups are doing so either for Overclocking, Elaborate Watercooling, or Cause e-peen. These are the true enthusiasts and will likely be the most vocal over the whole situation
We likely won't know the real answer until after Computex as the official info is likely still under NDA. This would explain why the YouChubbies are doing videos later after their disclosure agreements expire and why the answer at the EVGA forums was retracted.
Thing is, unless NVIDIA pulls a GTX 770 the card will support 4-way configurations, they are just pushing the High Speed Bridge (HSB) because its awesome and new.
