Mac Mini M4 with external monitor - how to use M1 MBP as extended display without lag

epcards wrote:

Just got the Mac Mini M4 and connected it to my external monitor via HDMI. I went into the display settings and toggled the extended display to my M1 MBP, but there seems to be a lag when the mouse is on my MBP screen.

I've read that it's possibly a refresh rate or cable issue but everything seems to be OK? Any suggestions on how to fix this?

As you have found out, AirPlay to Mac is not as good as a hardware-supported connection to a real monitor. There are several things that contribute to this:

• It's a software-driven method. General-purpose CPUs aren't optimized for the task of driving monitors, and also may have competing demands for their time ("running your programs").
• The packets often go over Wi-Fi, which may introduce additional delays, especially if there's a lot of interference (from neighbors' Wi-Fi routers, from microwave ovens, from wireless baby monitors, etc.).
• The selection of resolutions is very limited, and might not be a good match to the device being used as a display.

You might not be able to do much to "fix" it. Then the question would be whether it's better to use it, warts and all, or not.

If you are wanting a sweet dual display setup..?

Consider getting a second matching external display for the M4 Mac mini.

see > Connect a display to Mac mini - Apple Support