A:Answer We had a similar problem. It would not run 144mz with the HDMI cable we already had, just flickered on and off when we chose 144 in monitor settings. We had to use the cable that came with the monitor for it to work. You need a high-speed HDMI cable to set it up for 144hz. Once connected, you should be able to select 144hz in your settings. Our computer selected it automatically.
Hope this helps!