External monitor and MBP not playing well together

Question

External monitor and MBP not playing well together

Yesterday I replaced my external display from Lenovo G25-10 to Lenovo G27g-30.

I have the MBP set to main display and the Lenovo G27 as extended display.

The problem I'm facing is the Lenovo G27 will only run at 1080p (although my MBP is suggesting 2560x1440 is default on the options). The MBP in built display is set to default (1680x1050). Apple suggest simultaneous support for inbuilt display and up to 2 displays with 5120x2880 so this set up should be fine, right?

New monitor is Lenovo G27g-30 running on HDMI (wasn't sure if this was the issue)

MBP is a 2018 2.6Ghz, 6-core i7 with 16Gb and 560X graphics.

Anybody know if it's something I've done wrong?

Posted on Aug 12, 2023 04:46 AM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

138,635 points

Aug 12, 2023 01:53 PM in response to nobodylikechange

Lenovo G27-30Q:

Maximum Resolution 2560 x 1440

from:

https://www.lenovo.com/us/en/p/accessories-and-software/monitors/gaming/66e8gcc2us?orgRef=https%253A%252F%252Fduckduckgo.com%252F

if you can't attain higher than 1920, the most likely problem is trying to use consumer cables for a comparatively high end HDMI display.

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

HDMI was invented for HD TV sets. it works great at its original resolution of 720i or 720p. At higher resolutions, it quickly develops issues that are complex to solve, and the cables and adapters required to solve are NOT intuitive.

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Answer 2

Aug 12, 2023 12:50 PM in response to nobodylikechange

The Mac uses a system that reminds me of “Plug and play” to determine what display is connected, and what its capabilities are.

To get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

This also means that if the display provides WRONG information, the Mac will attempt to use that wrong information.

On a PC, you set display resolutions manually or with a side-loaded display profile off the Internet. So if the internal display capabilities are wrong on a display mostly used on PCs (like Lenovo displays) it could be a quite a while before the manufacturer says oops and MAY issue an update (or may not).

Recommendation: since you KNOW this is a 1920 by 1080 display, just set it manually to that or lower.

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Answer 3

Aug 12, 2023 01:05 PM in response to Grant Bennet-Alder

Hi, thanks for chipping in. I think I follow your point(s). It’s frustrating as this is not a 1080 display but 1440 which only works when set to 1080… do you think the monitor is been programmed to think it’s 1080?

The only think I’m thinking might be limiting the resolution is the cable (HDMI). Will try a display port cable as I read this can transfer more data at higher rates.

Ive tried the detect screen (using the option button but it does nothing - that said it already knows there’s a screen attached but can’t get past 1080

Am I right to say (based on Apple’s specs) my MBP should easily be able to drive the inbuilt display and a 1440p monitor together because even setting the MBP to drive the external monitor only results in nothing better than 1080p.

a little disappointing as I wanted a bigger screen but not at 1080.

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Answer 4

Aug 13, 2023 08:34 AM in response to Grant Bennet-Alder

Update for anybody else facing the same issue.

Now working after ordering a Display Port to USB C adapter. Annoyingly my MBP didn't recognise the new DP cable (or monitor) and had to manually set the extended display at 2560x1440 and change (on the monitor) from HDMI to Display Port (the monitor's auto detect didn't do this either). I was also surprised as I'm 99% sure my HDMI cable is meant to be able to transmit 4K (in fact I've used it on our 65" TV although I never checked what resolution the TV was running at when watching).

Anyhow, very please now screen has a better resolution, 1080 was okay but 1440 is better.

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Answer 5

Aug 13, 2023 08:42 AM in response to nobodylikechange

<< my HDMI cable is meant to be able to transmit 4K >>

You may have stepped directly into the land-mine that is higher-end HDMI.

Cables actually capable of those speeds are labeled as I wrote above:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

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External monitor and MBP not playing well together

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