Macbook Pro M1 2020 to two Thunderbolt displays

Hi,

As far as I know, you can't connect two Display to MacBook Pro M1 model.

Use one or more external displays with your Mac - Apple Support

The 2020 Apple-Silicon M1 13-in MacBook Pro and Air are extremely-capable entry-level computers. They can support the internal display AND an External display up to the previously unheard of size of the Apple 6K display at billions of colors. But only ONE in addition to the internal display.

This may not match the way older computers forced you to work, since older computers were not able to support a really large external display. But it is NOT a defect. The spec was available long before you could purchase the computer.

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Fetching screen data is done by rasterizer/display-generator Hardware in the graphics subsystem. Once set up, data are fetched at that same interval again and again without additional intervention. The entire screen data MUST be completed within each screen refresh interval (often 1/60th second) or the screen will go partially or completely blank without the late or missing data. In addition, each one-pixel-tall Row must be fetched on a much tighter schedule within one row-time, or part of the row will be blank.

The MacBook Pro M1 memory features a "unified" memory design. Everything comes from that one memory array, with one memory access logic. Many devices are competing for access to the memory access logic, and screen refresh is especially urgent. In this M1 entry-level design, there is no more additional memory bandwidth to support more than the built-in display and one external display up to 6K in size. No additional rasterizer/display-generators can work correctly, because memory bandwidth is limited.

Executive summary: additional Hardware-accelerated display support can NOT be added to the entry-level 13-in M1 systems.