Scalable Link Interface, or in short NVIDIA SLI is a multi-GPU (Graphics Processing Unit) scaling engine, essentially a method of using more than one graphics card to boost in-game performance by up to +100% per additional GPU.
Commonly, SLI based systems are identified as being “n-Way” configurations, and within the context of this guide: “2-Way SLI” applies to any system using two graphics cards in sync; “3-Way SLI” for any system with three graphics cards in sync; and “4-Way SLI” denoting any system with four graphics cards or GPUs in sync.
By allowing multiple graphics processors to independently work on rendering a single 3D environment, we can theoretically multiply our frame rate by the number of new GPUs.
That paragraph is from the official NVIDIA SLI forums. However, the unfortunate truth is that the state of multi-GPU systems isn’t as rosy as they want you to believe. Now, I have a GeForce GTX 980Ti SLI rig, so I can comment on how well (or NOT) SLI works but I have little to no experience with X-fire but word on the street is that it’s not in tip-toe form either.
As far as SLI is concerned, officially NVIDIA stopped supporting 3-way and 4-support SLI setups when they announced the fancy HB SLI bridge along with the 10-series cards. I completely understand that decision since less than 1% of the users have more than 2 GPUs in sync.
However, you’d expect that because of introduction of the fancy new SLI bridge and the abandonment of >2-way configs, 2-way SLI should at least perform with acceptable results. That’s anything but the truth. Recently support has been really neglectful, with pretty much all recent video games going without any sort of multiple-GPU support for months after release. I’m not saying that the 2-way SLI performance is unsatisfactory. It’s just that it doesn’t work at all. Only one of the GPUs work while the other one just dozes off. I was really shocked when I made a list of recent games and checked how many of them actually support SLI. Don’t believe me. Alright here are some of popular games that have absolutely ZERO support:
HellBlade Senua’s Sacrifice.
Just Cause 3.
Resident Evil VII.
Sherlock Holmes: The Devils Daughter.
Sherlock Holmes: Crimes and Punishments.
The Vanishing of Ethan Carter.
Batman Arkham Knight.
These are the games (that I own) that still don’t have SLI support. Other AAA games like Deus Ex:Mankind Divided, Mass Effect Andromeda, Watch Dogs 2… received a proper SLI profile months after release.
Furthermore, games like Ghost Recon Wildlands and The Division use temporal filters with a lot of their graphics effects which pretty much cuts the SLI advantage in half, and if you manage to disable these filters one way or another, the game renders images plagued with aliasing. So…yeah there’s no way out.
Sure every once in a while someone accidentally or purposefully bumps into an SLI flag that works for some games, sometimes with more than decent scaling, but that’s not exactly reliable or consistent and there is no way consumers (including ME) who have paid a huge sum of money for their shiny new GPUs will consider these unofficial profiles sufficient, especially since it’s NVIDIA’s and the developers’ jobs to implement multi-GPU support. However, it’s not that simple.
The game developers keep blaming the manufacturers and vise versa. And to their credit they are somewhat right in their justifications. Implementing SLI takes up a lot of resources on NVIDIA’s side. Plus the percentage of multi-GPU users is 15% max.
On top of that, these days developers are making more and more use of temporal techniques like TAA, checkerbox rendering, Temporal filtering… These “temporal filters” are very efficient, but they essentially break AFR (Alternate frame rendering) which is the predominantly used form of multi-GPU rendring. This is because in these methods, every consecutive frame fetches some data about the previous frame, and since in AFR consecutive frames are rendered by different GPUs, that induces lags or increases the latency, effectively reducing the scaling by a significant margin.
Now I understand the pain of my fellow multi-GPU users, so I have been saving and storing the SLI profiles of all the games that I have been able to set them up for, sometimes myself after hours of frustration and trial and error while the rest rest were downloaded over the internet from a wide range of websites.
Here’s the list of games for which I have been able to figure out a working or slightly improved profile:
Dark Souls- works well.
Deus Ex:Mankind Divided- works well
Fallout 4- works well.
Mass Effect Andromeda- works well.
Mirror’s Edge Catalyst- works well.
Nier Automata- works well, but with slight flickering.
Rise of the Tomb Raider- works well.
The Division- works well, but TAA needs to be disabled for optimal scaling.
XCOM 2- works well.
Shadow Tactics- works well.
Sherlock Holmes:The Devil’s Daughter- works but slight flickering.
Sherlock Holmes:Crimes and Punishments- works well.
Those are all the profiles I know of. If you know about more profiles or fixes, do let me know in the comments. Also if you have any issues or problems be sure to inform me, I’ll help you out (Don’t worry, we WILL reply). Here is the link to the profiles, and yeah, you are going to need nvidia inspector to implement these fixes/profiles. It’s real easy, don’t worry. Give it a shot.