While the Apple M4 chip enables the connection of up to three external monitors, some users are experiencing issues, particularly with certain ultra-wide displays. This is despite the M4 chip supporting resolutions of up to 6K, 8K and 4K at various refresh rates.
The Issue: 5K 21:9 Monitors and HiDPI
Specifically, users are encountering problems with 5K monitors in 21:9 format (5,120 x 2,160 resolution). While these monitors work at full resolution, the "HiDPI" mode cannot be enabled. HiDPI scales a lower resolution (e.g., 3,840 x 1,620) to the native resolution for a sharper image. Interestingly, these same monitors work fine with older Macs using the same cables, suggesting the M4 chip is the source of the problem.
Workarounds and Lack of Official Response
Some users have found workarounds using third-party apps like BetterDisplay, but these are limited to a 60Hz refresh rate. While apps like SwitchRes X and EasyRes can also adjust resolutions, they may result in frame rate issues or reduced image quality. Apple has yet to comment on the issue, leaving users uncertain whether a fix is in development.
Those using M4 Macs with 5K 21:9 displays may need to wait for a solution from Apple or continue to use workarounds that may compromise performance or visual quality.
