As @Thmoas has said, you HAVE to use the video ports on your Nvidia card only.
I had the exact same problem you have when I first tried Google Earth VR, and the fix was to connect my TV to the Nvidia display port via a HDMI adapter.
Works an absolute treat now.
RIFT CV1
RIFT S
Leeds, UK.
Intel Core i7 7700K 3.7GHz | RAM 32GB DDR4 2666MHz | GeForce GTX 1080 8GB |
"Behind every mask there is a face, and behind that a story...."