RAM and GPU core effect on internal and external display resolutions

[hajime]

Hi, for very very old Mac, more VRAM meant more higher resolution choices and more color depths as long as the display was capable of. How is the case of Silicon Mac?

I read that unified memory can be used as both typical memory and also for video. In the case of the base model of MacBook Air 15", the maximum resolution MacOS provides is 2880x1864 (1710x1107 is chosen by default). If I add more RAM to, say 16GB, will I be able to increase the resolution of the internal screen?

In the case of M2/M2 Pro Mini and M2 Max Studio, if I add more RAM, will they allow more higher resolution options for external displays?

How the number of GPU cores affect the resolutions of internal and external displays?

 

[leman]

It does not. The resolution is limited by, well, resolution of the display and the capability of the video connector. While macOS can effectively use resolutions higher than native on hiDPI displays, you are limited to something like 1.5x the resolution if I remember correctly (as going beyond won’t make any sense).

The mere fact of driving a display consumes very little RAM or GPU resources. RAM bandwidth is often a bigger issue as the data has to be copied from the GPU to the display controller etc. The rest depends on what you actually do.

 

[hajime]

Thanks. Right now I am connecting a base model of MacBook Air 15" to a 4K display. Under Display of MacOS, the internal main display is set at 1920x1243 (the maximum resolution in the list). Although the resolution of the 4K display is set to 3840x2160 in extended screen mode (1920x1080 is also listed as default), the letters look very ugly. I did not have this problem when I used a base model of M2 Mini. What could be the cause and how to fix it?

 

[leman]

Define ugly? Is it blurry, or too small, or the colors are off? The 3840x2160 should be the default resolution of the external display, do scaling modes also look ugly or are they better? Some people have reported that Apple Silicon sometimes has trouble detecting the display correctly and sends the wrong video signal type (something about confusing it with a TV output). Maybe someone more knowledgeable with the matter can comment?

 

[hajime]

Letters are not crisp/sharp. I can see the dots forming the letters. Do not have this problem when using the 4K TV with a PC or Mac mini M2 and M2 Pro.

I am not familiar with scaling modes. I just went to Display and chose the 4K resolution from the list.

 

[leman]

Can you please try out resolutions and see if the problem is still there? I assume your Mini and Pro were connected using HDMI? It is possible that the USB-C connection with the Air is not correctly negotiated.

 

[Tagbert]

Letters are not crisp/sharp. I can see the dots forming the letters. Do not have this problem when using the 4K TV with a PC or Mac mini M2 and M2 Pro.

I am not familiar with scaling modes. I just went to Display and chose the 4K resolution from the list.

I assume you are right-clicking on the resolutions and choosing “display as list”.
then click the switch for “show all resolutions”. That will give you the most options.

4K 3840x2160 will make everything very small and likely hard to read.

There are several resolutions there that will display the UI at various sizes while still using the actual 4K resolution of the monitor to render them. This gives reasonable sizes for screen elements while keeping everything fairly crisp.

Avoid the “low resolution” modes. Those are not using the full 4K resolution And instead will leave things looking a little blurry and rough.

Try 2560x1440 That is a good compromise of size on most 4K displays. Text will be smooth, but large enough to read. Graphics will be rendering using the 4K resolution.

You can use the default 1920x1080 but that usually makes things a little too big and you lose a lot of screen space.