Getting Screen tearing with 90FPS on Showdown VR Demo

I am running an NVIDIA GeForce GTX 980.

At first I thought the jitteryness/tearing was due to poor framerate, but I was able to get my framerate to cap out at 90 after arranging my monitors as detailed here.

I also tried to eliminate the tearing by going into my NVIDIA Control Panel and turn VSync to On.

Are there any other steps I could try? Or is this an issue when using UE4 with the Vive? (I have seen this happen on several other projects)

Try the console command r.vsync 1