They all support two monitors (one internal and one external for macbooks, and two external for desktops). It’s not an artificial restriction. Each additional monitor needs a framebuffer. That’s an actual circuit that needs to be present in the chip.
What percentage of people who buy the least expensive MacBook do you think are going to hook it up to more than two displays? Or should they add more display controllers that won’t ever be used and charge more for them? I feel like either way people who would never buy one will complain on behalf of people who are fine with them.
Not necessarily. The base machines aren’t that expensive, and this chip is also used in iPads. They support high resolution HDR output. The higher the number of monitors, resolution, bit depth, and refresh rate the more bandwidth is required for display output and the more complex and expensive the framebuffers are. Another system might support 3 or 4 monitors, but not support 5K output like the MacBooks do. I’ve seen Intel systems that struggled to even do a single 4K 60 FPS until I added another ram stick to make it dual channel. Apple do 5K output. Like sure they might technically support more monitors in theory, but in practice you will run into limitations if those monitors require too much bandwidth.
Oh yeah and these systems also need to share bandwidth between the framebuffers, CPU, and GPU. It’s no wonder they didn’t put 3 or more very high resolution buffers into the lower end chips which have less bandwidth than the higher end ones. Even if it did work the performance impacts probably aren’t worth it for a small number of users.
TIL, thanks! 🌝
I use a Plugable docking station with DisplayLink with a base-level M1 MacBook Air and it handles multiple (3x 1080p) displays perfectly. My (limited) understanding is that they do that just using a driver. So at a basic level, couldn’t Apple include driver support for multiple monitors natively, seeing as it has adequate bandwidth in practice?
Sigh. It’s not just a fricking driver. It’s an entire framebuffer you plug into a USB or Thunderbolt port. That’s why they are more expensive, and why they even need a driver.
A 1080p monitor has one quarter of the pixels of a 4K monitor. The necessary bandwidth increases with the pixels required. Apple chooses instead to use the bandwidth they have to support 2 5K and 6K monitors, instead of supporting say 8 or 10 1080p monitors. That’s a design decision that they probably thought made sense for the product they wanted to produce. Honestly I agree with them for the most part. Most people don’t run 8 monitors, very few have even 3, and those that do can just buy the higher end model or get an adapter like you did. If you are the kind of person to use 3 monitors you probably also want the extra performance.
