Too low resolution on external monitor when switching from HDMI to Thunderbolt (with HDMI adapter)

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Too low resolution on external monitor when switching from HDMI to Thunderbolt (with HDMI adapter)

Heyya!

I have a rather old MacBook pro (details below), that I've been using with an external Samsung monitor (details also below). The external monitor is Ultra Wide Screen with high resolution, and I've been using it by plugging it in to the HDMI port on my laptop. It's been working fine for years.

Recently, my laptops HDMI port has broken down. I can no longer plug my monitor in there. So instead, I bought a Thunderbolt-to-HDMI adapter, and plugged it in via the Thunderbolt port on my laptop.

This works, I'm getting a picture, but the resolution maxes out at 1080p (even with option-click scaled resolution options in display settings), which is way lower than the screens 3440x1440 intended resolution.

Do you know how I can resolve this, and get my secondary monitor up to full resolution?

Earlier Mac models

Posted on Aug 9, 2023 3:52 AM

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Answer 1

Best reply

Grant Bennet-Alder

Level 10

126,991 points

Aug 9, 2023 12:40 PM in response to Johnb-one

That display also appears to have a DisplayPort input, so you could use an adapter like this one:

Monoprice USB Type-C to DisplayPort 3.1 Cable - 5Gbps, Active, 4K@60Hz, Black, 6ft - Product # 24444 -$14.96

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Answer 2

Johnb-one

Level 6

9,156 points

Aug 9, 2023 8:45 AM in response to simonrmortensen

Uh, maybe, simonrmortensen, you have to make sure the adapter supports HDMI 2.0 and HDCP 2.2, HDMI 1.4 maxes out at 1080 and won't go any higher than that... I think this might be your MacBook Pro's model and specs??

MacBook Pro (Retina, 15-inch, Mid 2014) - Technical Specifications (CA)

so, it'll do 1080 at up to 60 hz, 3840x2160 at 30 hz, and 4096 x 2160 at 24 hz, for HDMI only, other than that, see if a reset smc/pmu and 4 pram zaps on startup of your mac pro helps anything, per this link:

https://www.macworld.com/article/224955/how-to-reset-a-macs-nvram-pram-and-smc.html

John B

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