Mac Mini not registering correct size of BenQ monitor

[RobArtLyn]

I have a 2014 Mac Mini running 11.2.3 connected to a 27" 4K BenQ SW 271 by HDMI. The Mac registers the BenQ as a 61" monitor instead of 27" at the correct resolution of 3840x2160, which causes the text to be too small. I have temporarily worked around this by scaling the output to 2560x1440. The problem also happens when connected by DisplayPort. So far, both Apple and BenQ technical support have been useless.

Has anyone else experienced this sort of problem? Found a solution?

 

[Fishrrman]

My guess is that the Mini is "seeing" the display, NOT as "a display", but rather "as a tv".

Having said that, it's not the "size" of the display that matters, but the resolution.

3840x2160 is the correct (native) resolution for a 4k display in actual 4k mode. And yes, if you run it this way, the onscreen display will likely be "too small" to actually be useful.

For a 27" 4k display, the "proper" (most common) Mac setting is to run it in "HiDPI" mode -- i.e., "retina" mode ("pixel doubling").

That will yield a "perceived" image that is 1920x1080, or "looks like 1080p".

Try opening the displays pref pane.
HOLD DOWN THE OPTION KEY, and clicked the "scaled" button.
Do you see the "1080p" option?
If so, try it.

Be aware that you CAN run it in "scaled" mode (as you're doing now), but doing so puts a lot more "load" on the internal graphics.
Running it in "looks like 1080p" does not "load it down" as does scaling it.

 

[RobArtLyn]

My guess is that the Mini is "seeing" the display, NOT as "a display", but rather "as a tv".

Having said that, it's not the "size" of the display that matters, but the resolution.

3840x2160 is the correct (native) resolution for a 4k display in actual 4k mode. And yes, if you run it this way, the onscreen display will likely be "too small" to actually be useful.

For a 27" 4k display, the "proper" (most common) Mac setting is to run it in "HiDPI" mode -- i.e., "retina" mode ("pixel doubling").

That will yield a "perceived" image that is 1920x1080, or "looks like 1080p".

Try opening the displays pref pane.
HOLD DOWN THE OPTION KEY, and clicked the "scaled" button.
Do you see the "1080p" option?
If so, try it.

Be aware that you CAN run it in "scaled" mode (as you're doing now), but doing so puts a lot more "load" on the internal graphics.
Running it in "looks like 1080p" does not "load it down" as does scaling it.

Actually, the recognized physical size does matter. I am also using this display with a Mid 2015 MacBook Pro. It correctly reads the display as a 27" monitor at 3840x2160 and everything is appropriately sized when the preference is set to "Default for display". Scaling not needed.

There is no need to hold down the option key when selecting "Scaled". There are seven different options including both 1920x1080 and 1080p. I have no idea why I would want to pay $1K for a color managed 4K display to only run it at that resolution. Running at as a 2K display is barely acceptable.

I am aware of the "TV" problem, but everything that I have read associates it only with HDMI. The problem persists when I use DisplayPort.

It's either a Mac Mini problem or a Big Sur problem.

 

[Fishrrman]

"It's either a Mac Mini problem or a Big Sur problem."

No.
It's your problem. You don't understand what's going on.

A 4k display has a native resolution of 3840x2160 regardless of the size of the display.

A 27" 4k display has the same number of pixels as does a 32" 4k display, or a 24" 4k display. A 4k tv set has the same number of pixels, whether it's 40" or 65".

The overal size of the display has NOTHING to with this. The pixel size "is what it is".
On a 27" 4k display, the pixel size is .1557mm.

To verify that for yourself, go this page:

DPI Calculator / PPI Calculator

It doesn't matter "what size" of display the Mac reports... the physical pixel size cannot be changed on the display. Again, it is what it is.

You fail to understand what the concept of "retina" means on the Mac.
A retina display has FOUR TIMES the number of pixels as what the display is intended to "look like".

Thus, a "4k" display, when used in retina mode (also called "HiDPI mode") on a Mac will use 4 pixels to display "the perception of a single pixel".

That's why you see "1080p" in the displays pref pane, etc.

When you display at 2560x1440, you are choosing a resolution that "looks like" 1440p.

If 1440p looks "good enough", use that.
But be aware that using a scaled (as distinguished from "pixel doubled") resolution can "eat up" processing power. This could cause the Mac to heat up, and the fans to run.

But a 27" 4k display, to run in true "pixel doubled" mode (looks like 1080p), is the way the Mac OS will run best. It will run well in full 4k, but again, the text will be too small to be readable (at normal font sizes).

There is a way to force the Mac to see the display "as a PC display" and perhaps not "as a tv". You can find out how to do that here:

ireckon.net

 

[RobArtLyn]

I know how to count pixels. I am also not delusional enough to think that a software setting changes the physical size of anything.

Same monitor. Two computers. One has it right. One has it wrong. Guess which computer exhibits expected UI element size and behavior.

 

[Fishrrman]

Re-read the final paragraph in reply 4 above.

Another thought:
Could it be the cable/adapter ?
Changing that might be the solution.
Something "in the cable" (or adapter) may be the cause of the Mini "misinterpreting" the physical size of the display.

But again, the size makes no difference. It shows the same number of pixels.
3840x2160 is going to look the same no matter which computer you connect it to.

Take a phone snapshot of the two Macs, and post those here for all to see.

 

[gnasher729]

Re-read the final paragraph in reply 4 above.

But again, the size makes no difference. It shows the same number of pixels.
3840x2160 is going to look the same no matter which computer you connect it to.

The physical size makes a huge difference. If you have a 27" 3840x2160 pixel monitor MacOS will treat it as a retina display, that is it displays 1920x1080 points at higher quality. If you have a real 61" 3840x2160 pixel monitor MacOS will treat it as a non-retina display, that is it displays 3840x2160 points at low quality. On both monitors, text will be about the right size, but you can fit four times as many points on the 61" screen, at lower (non-retina) quality.

If MacOS incorrectly believes that you have a 61" 3840x2160 pixel monitor when in reality you have a 27" monitor, it will try to display 4 times as much information on the display, at non-retina quality, and the result is that everything is displayed much too small.

 

[chrfr]

But again, the size makes no difference. It shows the same number of pixels.
3840x2160 is going to look the same no matter which computer you connect it to.

If the difference were that the display was, say a 24", and was being reported as 27", then yes, you would be correct. In this case, however, the system does not handle the 2 sizes the same way.

 

[Fishrrman]

I want to see pics that prove what the OP is saying.

A 4k 65" tv set has exactly the same number of pixels as does a 4k 27" computer display.

Yes, the pixels are LARGER on the 65" display.
But the NUMBER of pixels is exactly the same.

If you configure the displays pref pane for 3840x2160, then you're going to get "native resolution" on both the tv and the display.

On the tv, this is "normal".
On the 27" display, text will be very small (when displayed at normal font sizes).

If you configure the displays pref pane for 1920x1080 (which the Mac seems to do with 4k displays as a default), the Mac OS doesn't care what the SIZE of the display is. It just sends 1920x1080 pixels to it through the connecting cable. If it's a 4k display, it goes into HiDPI mode, and "doubles the pixels", creating an image that "looks like 1080p", again 1920x1080.

If this isn't the case, what feature of the OS/displays panel "interprets" the physical dimensions of the display, and makes the according "adjustments"?

I wouldn't want to use "true 4k" on any display smaller than 50".
For me, the text would be unreadable.

 

[IronMonkey415]

Everything works fine, but I do see what he is talking about.

I'm using a 2014 Mac Mini version 10.14.6 (Mojave) on a BenQ PD2700U monitor.

I have to use 1080P to get the screen to look normal.
If I pick 3840 x 2160 it will make everything small and hard to read.

I also see the same thing he is seeing, the Mac Mini shows that this is a 61" TV.