Acer XB280HK will not output anything other than 24hz

[Colonelkleenex]

I'm pretty much at my wit's end here.

I have an Acer XB280HK 4K G-sync monitor that out of the box displayed 3840x2160@60hz.

Now this morning out of the blue the monitor started outputting only 24hz. I have searched through the internet and found little to no other problems like this one.
Things I tried :
-Creating a custom resolution with 60 hz with nvidia control panel. Once "created", it doesn't even appear on the selection. and everywhere it still says it's at 24hz.
-Change the refresh rate in Windows in the screen resolution menu.
-Look through the monitor physical options menu to see if anything could be changed there
-Updated drivers (368.39)
-Changed the display port on my GPU.
-Also checked the see all resolution options, and none of them offer 60hz.

GPU is a GTX 980ti

I'm pretty much ready to hear anything from you guys, thanks for any help you guys are ready to give.

Just a quick edit, I plugged my monitor into another PC with a GTX 680, and while it was defaulted to 24hz, I was able to change the refresh rate in nvidia control panel and then in the windows screen resolution menu.

 

[Colonelkleenex]

Good news everyone

After seeing this thread : https://forums.geforce.com/default/topic/946864/geforce-1000-series/gtx-1080-fe-stuck-to-24hz-refresh-rate/

Someone suggested disabling the PCI-e UEFI boot. Having nothing to lose, I went into the bios(Gigabyte Z170XP SLI), didn't find anything resembling it, but I did find an option to disable internal graphics, which I did. Came back to desktop, and the options in nvidia control panel for 60hz was there, and changed it in the windows screen resolution menu.