External monitor resolution problem

[snic]

I just got a new SP4. When I plug it into a monitor (mini display port to HDMI adapter), the maximum resolution I can select is 1920 x 1080. However, the monitor's native resolution is 2560 x 1080, and using exactly the same adapter and cable, my Surface Pro 3 gives me 2560 x 1080 resolution on this monitor.

I've replaced the graphics driver with the latest version downloaded from Into (Iris 540), which provides a utility to set up a custom resolution. But, when I try to do that, the utility gives me an error saying "custom resolution exceeds maximum bandwidth capacity".

What is going on, and how do I fix this?

 

[PCAnyWhere]

I've only been able to resolve it by converting to the other inputs on the monitor. HDMI works fine on my 1440p monitor but my 1980x1200 monitor requires a VGA DSUB connector. I tried the HDMI and the DL-DVI and couldn't get beyond 1080p. I am also using the Surface Dock. I spent a bunch on cables and adapters to get one that consistently worked.

 

[snic]

So after going through several MDP-HDMI adapters, none of them worked. When plugged into the Surface, the best the monitor would display was 2560 x 1080 at 40 Hz (it's capable of 60 Hz). When plugged into the dock, the monitor absolutely refused to work except at very low resolution - and even then, there was weird audio static on the monitor's speakers.

What FINALLY worked was to get a mini display port to display port cable. The monitor has a display port input, so I eliminated adapters entirely.

One thing to note, in case anyone is having similar difficulties: this second monitor is actually about 10 feet away from the Surface and dock (I use it for a treadmill desk, and switch between the first monitor at a sitting desk and this monitor). The long HDMI cable (20+ feet) may have been part of the problem - I didn't test it with a shorter cable. I did find that the 15 foot MDP-DP cable works fine, but adding a 6 ft Display Port extension cable caused the image to become unstable (jumped around, sometimes screen went black). So if the bottom line is that long monitor cables might pose a problem when using high resolution displays with the Surface Pro 4 (but not, oddly enough, the SP3).

Now, if only I could figure out how to get Windows+P to show me options for selecting just one of each of the three screens, I'd be in paradise.