LG 40WP95C won't show the option for 5120x2160 @ 72Hz on Mac Mini 2018 using Thunderbolt cable

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Level 1

8 points

LG 40WP95C won't show the option for 5120x2160 @ 72Hz on Mac Mini 2018 using Thunderbolt cable

At 5120x2160, only 30Hz and 50Hz are available.

According to the user manual, 5120x2160 @ 72Hz is a supported configuration on Mac mini (2018).

This solved question didn't work for me - I never turned on the "Thunderbolt Out" setting. I tried "Reset to Initial Settings" with no change. No matter what I try, only 30Hz and 50Hz appear in the menu.

Other things I've tried:

turning on and off "Thunderbolt Out"
changing cables (I'm using the one that came with the monitor that has the Thunderbolt logo on it)
installing SwitchResX (trying to force 5120x2160 @ 72Hz gave a "Not activated - invalid" error)
rebooting countless times

I'm getting a new M2 Pro Mini in a month, so this will likely be solved by a newer computer, but it's frustrating that the manual that came with the monitor explicitly claims 5120x2160 @ 72Hz is supported with "Mac mini (2018 and later)".

I just noticed that I have a pending update to macOS 13.4, so I'll try that.

Mac mini (2018)

Posted on May 28, 2023 6:22 PM

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Answer 1

Top-ranking reply

Malcolm J. Rayfield

Level 7

23,115 points

May 28, 2023 7:36 PM in response to mjmvisser

The 2018 Mac mini doesn't support displays faster than 6oHz.

Mac mini (2018) - Technical Specifications

"Up to three displays:

Two displays with 4096-by-2304 resolution at 60Hz connected via Thunderbolt 3 plus one display with 4096-by-2160 resolution at 60Hz connected via HDMI 2.0

Up to two displays:

One display with 5120-by-2880 resolution at 60Hz connected via Thunderbolt 3 plus one display with 4096-by-2160 resolution at 60Hz connected via HDMI 2.0"

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Answer 2

May 29, 2023 12:02 AM in response to mjmvisser

I'm looking at the LG monitor manual, and I don't see any mention of the Mac Mini. The specifications say that the maximum resolution is 5120x2160 @ 72 Hz (DisplayPort/Thunderbolt/USB-C). They manual also says that you should use the top Thunderbolt port to make a Thunderbolt connection to a computer.

It also says "In accordance with PC products may not support the recommended resolution or some features." My take on that is that if the computer does not support 72 Hz, you're not going to get 72 Hz.

https://www.lg.com/us/support/product/lg-40WP95C-W.AEU

Apple's technical specifications for the 2018 Mac MIni says that it supports 5120x2880 resolution at 60 Hz. They don't list a maximum refresh rate for 5120x2160, but it seems quite possible that that rate is 60 Hz, in which case the 2018 Mac Mini and the LG display might try to negotiate the highest rate they have in common (50 Hz?).

Mac mini (2018) - Technical Specifications

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Answer 3

May 29, 2023 7:26 AM in response to mjmvisser

Given that LG is making the claim, and Apple isn't, I'd suggest contacting LG.

If their support people say they don't know anything about it – e.g., because they're looking at the same user manual that they have posted on their site – send them a copy of that photo. Then ask them nicely to either (a) explain how to get that resolution at that refresh rate, or to (b) admit that the "Graphic Card Requirement" contains a mistake.

The front-line support people may not know enough about the product to answer the question in other than a rote way (reading all the stuff you can read for yourself in the manual), so you might need to get them to escalate the question to someone in their Engineering department.

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Answer 4

den.thed

Level 10

94,330 points

May 28, 2023 9:13 PM in response to mjmvisser

DisplayPort can offer higher resolutions at higher refresh rates.

I would test an 8K USB-C/Thunderbolt to DisplayPort 1.4 cable with that 40” wide screen display.

for example > https://www.amazon.com/Silkland-DisplayPort-Thunderbolt-Compatible-MacBook/dp/B09M38CXZ3/ref=mp_s_a_1_2_sspa?

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Answer 5

den.thed

Level 10

94,330 points

May 29, 2023 7:05 AM in response to mjmvisser

A DisplayPort cable can offer higher refresh rates.

Test an 8K USB-C/Thunderbolt to DisplayPort 1.4 cable with that 40” wide screen display.

for example > https://www.amazon.com/Silkland-DisplayPort-Thunderbolt-Compatible-MacBook/dp/B09M38CXZ3/ref=mp_s_a_1_2_sspa?

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Answer 6

bjorn181

Level 1

8 points

Jul 26, 2023 1:12 PM in response to mjmvisser

Hello there,

I had the same problem and solved it by turning off "Thunderbolt out".

After that I was able to set it to 72 Hz in (Apple-)Settings.

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Answer 7

May 29, 2023 12:10 AM in response to Servant of Cats

RE: "And as I said, this monitor is explicitly advertised as achieving 5120x2160 @ 72 Hz on a Mac Mini (2018 and later)."

I'm looking at LG's product page, and I don't see any mention of the Mac Mini there.

https://www.lg.com/us/monitors/lg-40wp95c-w

If there is explicit advertising elsewhere, and it's LG advertising a refresh rate in excess of Apple's specifications, it sounds like a matter that you ought to take up with LG.

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Answer 8

May 29, 2023 12:25 AM in response to Servant of Cats

RE: "At the very least, I'd expect 60Hz to be an available option at 5120x2160. It is not."

LG's manual doesn't list 59.985 Hz as an available vertical frequency for a Thunderbolt connection - only as an available vertical frequency for a DisplayPort one. Maybe that has something to do with it?!?

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Answer 9

mjmvisser Author

Level 1

8 points

May 28, 2023 8:10 PM in response to Malcolm J. Rayfield

(No change after updating to latest Ventura 13.4.)

Thanks, but the bandwidth required for 5120x2880@60 is 10% greater than that required by 5120x2160@72.

5120*2880*32*60 = 28.3G b/s

5120*2160*32*72 = 25.4 Gb/s

And as I said, this monitor is explicitly advertised as achieving 5120x2160 @ 72 Hz on a Mac Mini (2018 and later).

At the very least, I'd expect 60Hz to be an available option at 5120x2160. It is not. Here's what cscreen reports:

✗ cscreen -v
DisplayID  Index     Depth     Width     Height  Refresh
1b672700       1        32      3440       1440    72
1b672700       2        32      1024        768    60
1b672700       3        32       800        600    60
1b672700       4        32       640        480    60
1b672700       5        32      1920       1080    60
1b672700       6        32      1920       1080    60
1b672700       7        32      1280        720    60
1b672700       8        32       720        480    60
1b672700       9        32       640        480    60
1b672700      10        32      5120       2160    50
1b672700      11        32      5120       2160    30
1b672700      12        32      2560       1080    50
1b672700      13        32       640        480    50
1b672700      14        32       800        600    50
1b672700      15        32      1024        768    50
1b672700      16        32      1280        960    50
1b672700      17        32      1280        540    50
1b672700      18        32      1344       1008    50
1b672700      19        32      1344        566    50
1b672700      20        32      1600       1200    50
1b672700      21        32      1600        674    50
1b672700      22        32      1920        810    50
1b672700      23        32      2048        864    50
1b672700      24        32      2304        972    50
1b672700      25        32      3008       1268    50
1b672700      26        32      3200       1350    50
1b672700      27        32      3360       1418    50
1b672700      28        32      3840       1620    50
1b672700      29        32      4096       1728    50
1b672700      30        32      4608       1944    50
1b672700      31        32      2560       1080    30
1b672700      32        32       640        480    30
1b672700      33        32       800        600    30
1b672700      34        32      1024        768    30
1b672700      35        32      1280        960    30
1b672700      36        32      1280        540    30
1b672700      37        32      1344       1008    30
1b672700      38        32      1344        566    30
1b672700      39        32      1600       1200    30
1b672700      40        32      1600        674    30
1b672700      41        32      1920        810    30
1b672700      42        32      2048        864    30
1b672700      43        32      2304        972    30
1b672700      44        32      3008       1268    30
1b672700      45        32      3200       1350    30
1b672700      46        32      3360       1418    30
1b672700      47        32      3840       1620    30
1b672700      48        32      4096       1728    30
1b672700      49        32      4608       1944    30

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