Acer xr382cqk resolution and refresh rate help

jakesno

When I setup the monitor last week I followed the limited manual directions and plugged in the HDMI2 and DisplayPort into the GPU after installing drivers although I'm still not convinced I've installed all of the drivers.  The HDMI connection worked, however the Displayport did not. I updated my ASUS HERO IX BIOS to a more recent stable version and now the Displayport works. Others have said the BIOS isn't relevant so...

However, initially when I used HDMI2 the BIOS and Nvidia control panel listed the advertised 3840 x 1600 at 75hz. Now that the BIOS has updated and the DisplayPort is activated I'm getting 2560 x 1080 at 60Hz.  The (recommended) values offered are Ultra HD 1080p, 1920 x 1080 also at 60Hz.

Specs:

ASUS HERO IX mobo BIOS v0806

Strix 1080 Ato8 gaming GPU, driver v381.65 (current)

16GB RAM

500GB M.2

Windows 10 Pro

 

How do I get 3840 x 1600 at 75hz?