Call it in and ask for fix or exchange.
I bought a new Gigabyte 1080 TI Gaming OC GPU to upgrade from my 980 TI and am having some display issues. When connecting to a monitor via a displayport cable I have a black screen shown on the monitor (Samsung u28d590d) and when I try to go in the menu on the monitor it keeps closing it, presumably because the output keeps refreshing or something.
If I use a HDMI cable from the same GPU into the same monitor it will output no worrys. If I plug in a second monitor with the original one connected via display port, suddenly both monitors will work, both in 1080p.
With both monitors connected I tried to increase the resolution to 4k and it will black screen until the timer runs out and it reverts to 1080p.
I have reinstalled drivers and they are currently at the latest (381.65) through GeForce experience.
Both the displayport and monitor previously worked fine until I installed the new GPU today.
Running Windows 10 Pro 64-bit (10.0, Build 14393)
Z170X-Gaming 3 motherboard.
I7-6700K CPU

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic