I connected my MacBook Air M1 with Lenovo R45W-30 but I'm not getting the highest resolution

Hi mohamud117,

We understand you're trying to get your Mac to send the best picture to your monitor.

You'll want to adjust the resolution as seen here:

Change your Mac display’s resolution

If you're not seeing the resolution you want available, try lowering the refresh rate until the resolution you want is available.

For further assistance, contact Lenovo for help:

Lenovo Support

Thanks for using the Apple Support Communities.

Hi, mohamud117, let's take a look at what your MacBook Air can output for video, this is according to Apple:

https://www.macworld.com/article/675869/how-to-connect-two-or-more-external-displays-to-apple-silicon-m1-macs.html, so 1 display output, up to 6k resolution and 60 hz, that's what it'll do....If you hold down the "Option" key while going to System Preferences>>Display>> Monitors (as you get to the Monitors/Display part of it, hold down the "Option" key, ) you should see "Scaled for Display" and "Native resolution" and that'll be it... apart from using a powered USB-C dock....and DisplayLink Software...

John B

The Lenovo R45w-30 is a 44.5" Ultra-wide monitor with a resolution of 5120 x 1440 pixels and a 170 Hz refresh rate. It has HDMI, DisplayPort, and USB-C (DisplayPort) inputs.

https://support.lenovo.com/us/en/solutions/pd500696-lenovo-r45w-30-overview

I would wonder whether the Ultra-wide aspect and/or the 170 Hz refresh rate were causing trouble.

That monitor has only about 89% as many pixels as a UHD 4K (3840 x 2160 pixel) monitor, so there ought to be enough bandwidth to drive it at 60 Hz using a USB-C cable or a USB-C to {DisplayPort, HDMI} adapter cable.