Is there a solution to slow performance on MBP15 2019 when lid closed clamshell?

Hi zorromiha,

Thank you for posting in the Apple Support Communities. It sounds like you're having some performance issues when using closed-display mode, correct? If so, we would love to help! Are you using an ultrawide or super-ultrawide external display? If you are, please visit the linked information we've provided for you below.

If the supported resolution isn’t available on an ultrawide or super-ultrawide external display connected to your Mac with Apple M1 chip

Please let us know if you have any additional questions. We're always happy to help.

Cheers!

Thanks for getting back to us, zorromiha!

Let's go ahead and check the requirements and setup, just to be certain everything is as it needs to be to work correctly.

Use multiple displays with your Mac Pro (2019)

If everything is good there, let's continue troubleshooting with the below link.

Get help with video issues on external displays connected to your Mac

Finally, if the issue remains, we recommend reaching out to Apple Support for additional help.

Get Support

Best of luck!

That's interesting indeed, zorromiha!

Are you using an Apple wireless mouse, or a third-party device?

Even though it seems to only happen when closed, let's go ahead and try the troubleshooting we've linked below.

If your Apple wireless mouse, keyboard, or trackpad isn't working with your Mac as expected

If it is a third party device, you may try checking to see if a driver update is needed from the manufacturer, and checking for interference.

Resolve Wi-Fi and Bluetooth issues caused by wireless interference

If the issue remains after you've tried those things, it may be best to reach out to Apple Support directly.

Get Support

Have a great day!