XPS 9560, ASUS PQ321 monitor, Mouse Lag / Ovetall Choppiness

Hello everyone,

I just recently (a week ago) purchased a new Dell XPS 9560 laptop. I am very happy and pleased with its performance when I'm using the laptop standalone.

However, when I connected the laptop via HDMI-HDMI to my ASUS PQ321 monitor, I experience input lag, my mouse isnt necessarily slow, but it's a little blurry and just the overall experience isnt as smooth on the external monitor.

I read online for solutions, I found a resist post that required updates to the Intel graphics card, which I did. I updated the BIOS through the dell update page, I updated the nvidia drivers as well as turned the battery to high performance. I've set the PhysX configuration processor to use the GTX 1050 graphics card.

None of these solutions work, and I'm very frustrated.

Curiously, when I turn the display resolution down to 1920x1080 ; 60p Hz refresh rate, it becomes very smooth. Almost as if I'm using it without an external monitor at all. As soon as I turn the resolution up to 3840x2160 (it's a 4k monitor)-- that's when the laggy/ blurred mouse and computer movement occurs.

Does anyone have any idea how to solve this issue regarding the external monitor? What am I doing wrong?

Thanks!