i have a little problem with my mac and external tv (LG 4K).

Macbook air 2012 (intel HD 4000) LG 43UJ6307

i connect macbook with MiniDisplayPort -> DVI -> HDMI (1.4). by default i cannot set resolution to 2560x1440 (max resolut. is fullHD) but i fix it by switchResX app (but this only app can change this resolution more than fHD). when i set resolution to 2k fonts are vert uggly and readble. when i connect my Desktop pc and resolution to same size fonts are pretty and more understandable. (in 2k and 4k).

i was disable in Settings -> General -> Use LCD Smoothing when available

How can i fix it ?

i saw thereis option for HIDPI but there is only two variants 960x540 (HIDPI) 850x450 (HIDPI)

1 Answer 1


It sounds like your TV is not correctly connected to the Mac, so that you only have Full HD resolution available instead of the UHD resolution you want.

I would suggest trying with a different cable from mini-DisplyPort directly to HDMI. This should give you the least amount of problems connecting to the TV. Ensure that the cable specifically supports 4k.

I have seen multiple times that even cables sold as HDMI 1.4 cables do not really support 4k with the Mac (I guess some companies deliberately re-label old cables). Specifically I have seen this also with expensive cables, where as a cheap HDMI cable from IKEA works without any problems.

  • on the same cable hdmi - dvi if i connect to PC integrated HD 630 Graphics (DVI) Windows 10, i got full 3860x2160 @ 30Hz , yeah i know that hdmi and dvi not support more than hdmi -full hd and dvi 2560. Resolution i can fix but font on mac looks very ugly and not readble on 2560x1600. for example on windows pc if set this resolution is more pretty and i can read something or write. i read that i need set force RGB and disable LCD Smooting Oct 21, 2017 at 11:04
  • You're not using the same combination of cables. I will still suggest the cable I mentioned above. The reason for the ugly fonts is probably the resolution. Check the input resolution on the TV's menu to determine which resolution you're really running.
    – jksoegaard
    Oct 21, 2017 at 17:45
  • ok, i'll try use combination of cables mini DP to hdmi and hdmi cable to TV. but i read somewhere that OS incorrectly detecting TV. i mean that i need use a monitor configuration for TV set a force RGB Oct 29, 2017 at 17:48

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