Apple silicon Mac gpu vram

There is no separate display RAM or VRAM. Screen data is fetched directly from main memory, the GPUs operate on main memory, the CPUs operate on main memory, and any part of main memory can be used as a display buffer, it does not have to be contiguous, and the allocation can change instantly.

That is the big benefit of "Unified Memory".

In theory, it could use almost all of main memory, like most of 16GB or 32GB on some models (just leaving enough for MacOS to not crash).

But how much RAM is available for Graphics is NOT good metric for comparing real GPU capabilities. Once you get above access to about 2GB of Display-RAM, the rest sits unused most of the time, and only called into use when you are doing very graphics-intensive stuff like applying filters and effects to images, or 3-dimensional modeling.

a 4K display uses 3840 by 2160 by 3 colors (at one byte per color) at HiDPI settings That is only a little more than 24 MegaBytes as display buffer. The rest of the Display-RAM can be used for computation and off-screen drawing so that the next image "snaps" onto the screen without lag, and holding a source image while transposing it into a destination image.

The amount of display-RAM available is generally not a constraint in commercially-available graphics systems, because the makers do not want to be embarrassed by not having enough for the worst-case use.

The GPUs can use any part of Main Memory. MacOS decides how much and where, and as I said, it need not be contiguous and can change instantly.

toluwalase290 wrote:

Then please what's the max memory amount it can use since it changes instantly?

Apple does not document that.

You could ask Apple directly, of course.

What is published here is between 16 GB and 64 GB.

If you’re deciding which memory capacity to order, I’d order the 16 GB configuration minimally. Or more.