HDMI vs DisplayPort output resolutions

I am connecting a MacBook Pro to an external 4K monitor and mirroring the displays. The display actually shows a warning with the actual resolution when the input is not 4K. If I select the "Best for ..." option in Settings, the output is 4K as expected. However, all other scaled options are outputting at 1080p. Is this expected? I saw somewhere that if I use DisplayPort instead of HDMI, I may have additional options, but I can't find any official documentation. Is that true?

Solution 1:

I saw somewhere that if I use DisplayPort instead of HDMI, I may have additional options, but I can't find any official documentation.

It depends on the capability of the monitor, the cables and the converters. If, for instance your monitor supported HDMI spec 1.4 but you used an older cable certified with the 1.2 spec, you'd be limited to the refresh rates you could use at certain resolutions (i.e. 120Hz at 720p). When connecting display devices (whether HDMI or DP), there's a number of variables you have to account for to ensure you're getting the best (or maximum) performance; it's not so simple to say "HDMI gives you this" or "DispayPort gives you that."

That said, I would say that DisplayPort provides you with better reliability than HDMI due to the fact that the native signal is DisplayPort. You have to convert that signal to get HDMI.

Now, when you convert, you introduce complexity and that can affect reliability and performance.

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