I have a brand new computer running Windows 10 Home with NVIDIA GeForce GTX 1070 and the refresh rate is stuck at 30hz, I have a choice of either 29 or 30hz, this monitor is supposed to have 60hz refresh rate. I've updated all my drivers, benq and nvidia as well as windows. The monitor is connected to the computer via the DVI cable. How do I fix this?
You would need to change the cable to a HDMI 2.0 or Display Port cable. That is the only way to connect with 60Hz. It is a cable limitation when running 4k resolution.
3840×2160at 60Hz (DP, HDMI-2)
3840×2160at 30Hz (DVI, HDMI-1)
Hope this helps,