I bought an ultra wide monitor (LG 29UM58) the other day. To hook it up to my Air, I convert a mini-DP signal to HDMI. With two different cables, I started noticing occasional latency on the signal where the screen freezes for about a second and then it becomes responsive again.
Some more interesting tidbits:
- This happens on my laptop screen as well as the external monitor while I'm connected to the display.
- I can use the on-screen menu of my monitor while my screen is frozen.
- I never had this issue with my previous screen, a 16:9 Full HD monitor with a DVI port.
- I tried an AmazonBasics Mini-DP to HDMI cable (maximum resolution of 1920x1080) as well as a Mini-DP to HDMI adapter from an obscure brand together with an HDMI-to-HDMI cable. Both gave the same results.
- I'm using macOS Sierra on a 2015 MacBook Air.
- My new monitor's native resolution is 2560x1080.
- The issue only seems to manifest while I'm moving my mouse, so there seems to be some interplay with mouse input and display output. I haven't seen it happen while I type yet.
- I tried reproducing the issue while a video was playing. Most of the time both the pointer and the video froze, but sometimes only the pointer froze. This makes me believe it's not related to the monitor itself or the cable.
How can I find out what's causing the random freezes and fix the issue?