[Darryl Ramm]

I would be surprised if Apple replaces the motherhood for the tower. It's not the kind of thing they have ever done before. But dang it would be a nice move if they did.

Their silicon may not have the horsepower for a while to replace the high end Xeon configs so the Mac Pro might be among the last model to get ARM processors. But for a future mother board swap to be most helpful it seems that's the kind of thing to announce well before it's available and give folks still needing to purchasing the Mac Pro confidence to keep doing so. But the high-end part of their Mac business is such as small market for them it may just not be worth the hassle.

The Mac Pro type machines today have external non-Apple GPUs and lots and lots of PCIe lanes. And that early Apple silicon may not have support for that. It's unclear if Apple will support multi-die packaging of silicon, that would be a very neat move a-la AMD that would let them get to higher-end configs faster. That's packaging is one of the top things I'm curious about to see in actual silicon details.

And beyond PCIe bus support what is the situation with Thunderbolt? Until now everybody has relied on Intel for thunderbolt support. With Thunderbolt becoming part of USB4 hopefully it will be carried over... but there is no Apple ARM based products today that has Thunderbolt support. I very much doubt Apple would abandon Thunderbolt but I hope to see that transition be smooth.

Intel has dragged their feet with PCIe 4, waved PCIe5 as futureware, and has had so many other woes recently. It would be good to see a future "Mac Pro" class machine at least using PCIe4. But early Apple silicon might well stick with PCIe3 to leverage of existing capabilities.

And on the software side there's the question of graphics support already mentioned, and there is the question of OS/driver low level support. Just what backwards compatibility will Big Sur or whatever OS then be running on ARM give to driver developers let alone being on a different ARM processor. We are already seeing challenges caused by recent macOS security features causing Avid driver issues for example. I would expect Apple to continue to focus on security and privacy aspects of their OS. What if it is not possible to disable SIP? What if they enforce stricter store/signage requirements for drivers etc. No reason to assume that will happen, but it wouldn't surprise me. Anything requiring a driver, from any vendor today is something to pay attention to. This is going to be fascinating.