Did I accidentally build a 5K Mac?.

[craighazan]

This confuses me a little, in system report Graphics/Displays reports that the TV I'm using as my monitor, HISENSE has a resolution of 5120 x 2880 (5K/UHD+ - Ultra High Definition Plus). I've set the UI in the system prefs to display 2560 x 1440 @ 60Hz, I can also set it to look like 3200 x 1800 or 3840 x 2160, but not 5120 x 2880, 5K.

 

[trs96]

This confuses me a little, in system report Graphics/Displays reports that the TV I'm using as my monitor, HISENSE has a resolution of 5120 x 2880 (5K/UHD+ - Ultra High Definition Plus). I've set the UI in the system prefs to display 2560 x 1440 @ 60Hz, I can also set it to look like 3200 x 1800 or 3840 x 2160, but not 5120 x 2880, 5K.

I've tested my RX 570 on a Hisense 4K TV and seen the same thing. It's obviously a 3840 x 2160 TV that doesn't support 5K. macOS is just reporting what the GPU is capable of, not the TV.

 

[shamgar]

MacOS handles high resolution displays by pixel doubling. The "looks like 1440p" option renders the UI at 5k and then downsampling to a 4k output. The displays tab of the System Info will report the actual output resolution, but the System Report details show the render resolutions instead when dealing with a non-Apple monitor.