980ti SLI Not Working Properly

[ChrisWKuiper]

Ok, I am having a fairly strange issue. My SLI appears to not be working.

I have 2 980ti's in sli, and when I go into the Nvidia control panel and enable it, it says its working. However, performance in games says otherwise. In fallout 4, I get only a 5 fps increase in sli, and a 0 fps increase in Star citizen and other games. I opened up GPU-Z to see what was going on, and with SLI enabled, it was showing that while one gpu was being used 80-90 percent, the other was being used less than 5% in all cases. Disabling and re-enabling SLI yielded the same results.

At this point I have no clue what to do, all of the drivers for nvidia are up to date. Also curiously in star citizen, gpu-z showed that the second graphics card memory usage was the same as the other one, but that the GPU itself was not working.

Any help would be great, thanks.

 

[Chugalug_]

That is simply as a result of poor SLI scaling, which in Star Citizen (given that it isn't a full release yet) is fully expected.
Fallout 4 is one of those iffier titles which I believe you have to fiddle around in to get a better SLI result, in addition to maybe a driver rollback, have a poke around.
Try it in something like Civ 5 or The Witcher 3 both of which have quite good SLI support.

 

[ChrisWKuiper]

That is simply as a result of poor SLI scaling, which in Star Citizen (given that it isn't a full release yet) is fully expected.
Fallout 4 is one of those iffier titles which I believe you have to fiddle around in to get a better SLI result, in addition to maybe a driver rollback, have a poke around.
Try it in something like Civ 5 or The Witcher 3 both of which have quite good SLI support.

Ok thanks, I will try civ 5 and get back to you. I did some more testing and got some better results off of gpu-z, but they still dont make any since. Basically SLI is correctly enabled, and the games are using both gpu's, but only at like 60-70% each. In both star citizen and fallout 4, running the games at 4k, both gpu's were at about 70% utilization, but the fps was only 50. If I drop the resolution to 1440p, the gpu utilization drops to 50% on each, and the fps goes up to 60 and stays there. So why doesn't the games just use more than 70% of each gpu to get 60 fps at 4k?

 

[photonboy]

1) Try a benchmark that works with SLI to confirm it works.

2) CPU may also be a bottleneck in some games.

3) May want to consider 2560x1440 instead for some games. Can get about 2x the FPS with visuals often looking about the same.