Of possible relevance here … per darthnVader.

Mac Mini G4 pixel clock limited to 135Mhz   / April 1, 2018
https://macos9lives.com/smforum/index.php?topic=4337.msg30099#msg30099

Display Support:   Single Display   Resolution Support:   1920x1200
Details:   The DVI video output supports digital resolutions up to 1920x1200. Apple also reports that it supports the "20-inch Apple Cinema display and 23-inch Apple Cinema HD display; supports coherent digital displays up to 154MHz; supports non-coherent digital displays up to 135MHz." VGA output (using the provided adapter) supports analog resolutions as high as 1920x1080. S-Video and composite video (to connect to a projector or TV) requires the Apple DVI to Video adapter (sold separately).


Coherent vs non-coherent is some obscure thing to do with the TMDS transmitter( on the GPU ) and the TMDS receiver in the display. The 9200 either has an issue with a weak TMDS signal with non-coherent receivers( Displays ). Or Apple crippled it, tho I doubt that.

The trouble is, no manufacturer really list that in the specs, and I doubt you'd get anyone in tech support to know what you were talking about if you did call them.

So it's really a crap shoot as to what brand and make of display will work correctly at the native res of the LCD/LED. My 1080p HDTV works fine with the Mini @720p, as the pixel clock is not over 135Mhz at that resolution.