I recently bought one of these cards and am having a weird issue with it.

Firstly, my setup
Intel i5-6600k running @ 4.2Ghz
Asus Z170A mobo
2x8gb Corsair something memory
iirc 650W psu
Running 398.11
 
Monitors/Tv:
1x 24" BenQ G2412HD @ 1080p 60hz
1x 24" Dell U2417H @ 1080p 60hz
1x 43" Sony XBR-43X800D @ 4k 60hz
 
I have the BenQ connected to onboard graphics and the Dell connected though a DP-mini DP converter and the TV connected through a 25' highspeed HDMI cable to the 1070.
 
When all the screens are on, everything works great but when the tv is turned off my dell monitor will get random screen flickering to a black screen with no set pattern in the time between flickers or how long they last. I have to unplug the tv's HDMI cable to stop it from happening. It appears to not happen when the default Windows drivers are installed or when I have the TV connected to onboard graphics. I have tried running the DDD (or whatever it's called) removal tool and did a fresh install of the drivers and it's still doing it. This card is about a month or so old right now so still under the warranty terms. I've done some reading around and it seems to be a fairly common problem and has many so called fixes but none of those things have fixed this problem. I'm tempted to get a hdmi -dp adapter for the tv to see if that will fix it but most adapters don't do 4k @ 60hz.
 
Anyone know how to fix this issue?

Would that actually be causing the problem, I'm using the cable that came with the dell monitor, so I have no clue what the specs on it are. Why would it only be doing it when the TV is off and not all the time?
 
EDIT: Let me clarify, the cable that came with the monitor is DP on one end and mini DP on the other, so no third party adapters.

I'll look into getting a replacement cable, do you know of a place which has Vesa cables that ships to Canada and won't be murderously expensive?

You can buy the cable from amazon... https://www.amazon.com/s/...ld-keywords=B143B-003J

Does the issue occur over all the dp outputs?