Slot Shaming
It’s the end of an era: Apple has confirmed to 9to5Mac that the Mac Pro is being discontinued. It has been removed from Apple’s website as of Thursday afternoon. The “buy” page on Apple’s website for the Mac Pro now redirects to the Mac’s homepage, where all references have been removed.
Apple has also confirmed to 9to5Mac that it has no plans to offer future Mac Pro hardware.
For the first time* since May 8, 1987, when the Macintosh II became available, Apple does not sell a Mac that offers built-in expansion slots.
That does not mean that Apple does not offer Macs that can be expanded. But this expansion happens through Thunderbolt 5, which offers PCIe 4.0 at 4x lanes (80 Gbps), or at slower specifications with lower versions of Thunderbolt or USB4. For comparison, the long-in-the-tooth, barely-worth-keeping-around Mac Pro from 2023 had PCIe 4.0, 2 slots with x16 lanes, 4 slots with x8 lanes and one slot with x4 lanes. The slowest slot is what Thunderbolt 5 is equal to. (Thunderbolt 5 does support boosting by reallocating lanes in its cable for workloads suited to this; instead of half capacity each way, it can do ¾ throughput (120 Gbps) one way and ¼ throughput (40 Gbps) the other.)
The pre-Apple Silicon Mac Pro, the first model of what we now know to be the final industrial design, and the final model to support GPUs, was released in a rack form factor to some confusion since it wasn't a server. Neil Parfitt, a music professional, explained his setup of it from a popular video at the time — basically, it solved the issue of hosting a bunch of expansion and interface cards, in a form factor that's suited to the industry's habit of half-rack units full of processing equipment.
With no Mac Pro, what would Neil use? He could hook up quite a bit of kit through Thunderbolt still, probably, especially since his Mac Pro generation used PCIe 3.0, and 4.0 is twice as fast for each lane, and so may have enough raw capacity to handle all of it. It is also likely the case that many interfaces do not need, or maybe even come close, to exhausting the throughput of PCIe 3.0.
What does matter in audio production is latency. Thunderbolt is a cable, when most PCIe slots are a handful of inches through one electrical trace away from the CPU. Thunderbolt does add processing delay compared to on-board slots directly.
No doubt a bunch of PCIe expansion chassis will appear to cater to the professionals that used the Mac Pro for its only remaining strength, its slots.
It will be very interesting to see how the workarounds will fare at solving problems for professionals that Apple were, until fairly recently, valuing highly enough to publicly apologize to.
* I was fibbing before - when they introduced the 2013 Mac Pro, they killed built-in expansion slots for the first time. The 2019 Mac Pro was the profuse excuse that brought them back.