
4K at 60Hz didn't work. However, 4K @30Hz works. The problem at 30Hz is that the mouse movement is very jerky and my expensive monitor feels cheap. It works fine at resolutions lower than 4K. Resetting the keyboard [Ctrl-Ctrl-R] doesn't work either, but the keyboard shortcuts to switch screens [Alt-Ctrl-1 or Alt-Ctrl-2] work fine. However, when my computers wake up from sleep, the keyboard and mouse are not recognized. I have to disconnect and reconnect the USB. It seems to be some kind of hardware race condition.

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