[kmeisthax]

The reason why non-Pro-chip MacBooks can't drive three displays is very simple: Apple gives each display its own SRAM buffer to scan out from, separate from the main system RAM. The display controllers on Apple chips are literally larger than the CPU cores because of this.

The reason why they do this is because it lets them run system RAM at lower power or suspend it entirely without affecting the displays. Which saves a good chunk of power - AFAIK after Asahi added support for the display coprocessor firmware (which implements this trick) they got a few extra hours of battery life.

My main complaint is that you can't turn off the primary laptop display to get an extra external display back. That's probably why most people need >2 display controllers in their laptops. Though AFAIK this may have been fixed in the M3?

[politelemon]

That isn't simple at all!