Hi,
I don't know if anyone is having this issue but before, I had an LG 34-UC97 and I plugged my Dell XPS 13 into it via HDMI and a HDMI to mini display port adapter. During that time period, it would display 3440x1440 on the monitor just fine.
However, I recently picked up the Acer Predator x34 and for whatever reason, it defaults to 1920x1080 and that is what is highlighted as recommended. I tried a different Laptop (Asus G51 JX-A1) and I found this to be a similar case. No matter what I tried, it would not go to 3440x1440 on the monitor.
For reference, the reason I'm using HDMI is because my display port is plugged into my main rig, which displays 3440x1440 just fine.
Does anyone know what seems to be the problem? Am I forgetting something?