External monitor shows up in settings with the ability for a higher resolution than rated? Why?

[slooksterPSV]

I bought a new monitor yesterday and it’s rated for 2560x1440 great! I plugged it in and checked the resolution settings and it does 3280x2160 umm what?? That resolution works. Mouse move slow across the display but doubt it’s 3280x2160 unless the scaling 75%.

Can someone explain or maybe I’m losing it for how I understood display resolutions work? Monitors have so many pixels so going more pixels doesn’t make sense. It seems like it has to be a scaling item. Thoughts? Maybe Sonoma bug?

 

[Bigwaff]

Would be most helpful if you would post your monitor brand and model number.

 

[slooksterPSV]

Would be most helpful if you would post your monitor brand and model number.

Sorry, it's an Acer Nitro EDO, ED270U

 

[anshuvorty]

IMHO, could be that the monitor is sending the incorrect EDID information to the Mac. In the past, when I encountered this bug and chose the higher resolution, the monitor failed to display anything because it isn't capable of displaying the higher resolution, and so, I just ignored it.

 

[MacGizmo]

It's simple. You have a display capable of showing 3840x2160 with the "Default" resolution being 2560x1440. It's just scaling to the larger size. If you switch to the higher resolution on that display, you'll notice that text is slightly less sharp.

Don't get too hung-up on display resolution scaling, people make much more out of it than it really is. If it looks good to you, use it – it doesn't really matter what is technically going on behind the scenes, nor do people's convoluted explanations of why scaling is good or bad.