You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Macbook pro 2017 detects wrong external monitor default resolution

Hi, I have a Lenovo p27u-10 UHD monitor and a MacBook pro 2017 with the latest OS version. When I connect the UHD monitor, it's default resolution detected is FHD (1920x1080) and I have to scale it in system preferences. But with scaling it starts lagging and slows down my Mac.

I tried to connect it via:

  • Thunderbolt cable from USB-C on the monitor to USB-C on the Mac
  • Cable DP on the monitor -> USB-C on Mac
  • HDMI-HDMI cable from the monitor to a USB-C hub, connected to Mac
  • Normal USB-C-USB-C 3.0 high-speed cable from the monitor to Mac directly

Nothing of that works ok.

However, I have a second QHD monitor Lenovo l24u, which works just fine via HDMI cable connected via a USB-C hub.

How can I make my Mac see the real default UHD resolution on the p27u-10 monitor?

MacBook Pro 13", macOS 10.15

Posted on May 24, 2020 9:33 AM

Reply
Question marked as Top-ranking reply

Posted on May 24, 2020 9:50 AM

SimnW wrote:

• Hi, I have a Lenovo p27u-10 UHD monitor and a MacBook pro 2017 with the latest OS version. When I connect the UHD monitor, it's default resolution detected is FHD (1920x1080) and I have to scale it in system preferences. But with scaling it starts lagging and slows down my Mac.
I tried to connect it via:
Thunderbolt cable from USB-C on the monitor to USB-C on the Mac
• Cable DP on the monitor -> USB-C on Mac
• HDMI-HDMI cable from the monitor to a USB-C hub, connected to Mac
• Normal USB-C-USB-C 3.0 high-speed cable from the monitor to Mac directly
Nothing of that works ok.
However, I have a second QHD monitor Lenovo l24u, which works just fine via HDMI cable connected via a USB-C hub.
How can I make my Mac see the real default UHD resolution on the p27u-10 monitor?



Mirror display also mirrors the display resolution. Extended desktop mode allows you to select the native resolution of the external display.


Try using Extended Desktop Mode instead of Mirror Display Mode.



Get help with video issues on external displays connected to your Mac - Apple Support
 https://support.apple.com/en-us/HT201177



Similar questions

3 replies
Question marked as Top-ranking reply

May 24, 2020 9:50 AM in response to SimnW

SimnW wrote:

• Hi, I have a Lenovo p27u-10 UHD monitor and a MacBook pro 2017 with the latest OS version. When I connect the UHD monitor, it's default resolution detected is FHD (1920x1080) and I have to scale it in system preferences. But with scaling it starts lagging and slows down my Mac.
I tried to connect it via:
Thunderbolt cable from USB-C on the monitor to USB-C on the Mac
• Cable DP on the monitor -> USB-C on Mac
• HDMI-HDMI cable from the monitor to a USB-C hub, connected to Mac
• Normal USB-C-USB-C 3.0 high-speed cable from the monitor to Mac directly
Nothing of that works ok.
However, I have a second QHD monitor Lenovo l24u, which works just fine via HDMI cable connected via a USB-C hub.
How can I make my Mac see the real default UHD resolution on the p27u-10 monitor?



Mirror display also mirrors the display resolution. Extended desktop mode allows you to select the native resolution of the external display.


Try using Extended Desktop Mode instead of Mirror Display Mode.



Get help with video issues on external displays connected to your Mac - Apple Support
 https://support.apple.com/en-us/HT201177



May 27, 2020 11:22 PM in response to leroydouglas

Unfortunately, I can't call the information under those URLs useful. There's no case when a wrong resolution is detected. Btw, my MacBook Pro works perfectly with my Samsung UDH TV. So it only can't detect the Lenovo p27u-10 UHD monitor's correct default resolution. Other laptops (on Windows) do it correct without any additional configuration.

All updates are installed on Mac

Macbook pro 2017 detects wrong external monitor default resolution

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.