On the Possibilities of the Apple silicon Mac Pro

Mark Gurman and Ian King have a new report out on Bloomberg about Apple’s plans for machines that will have better performance than the first three machines with Apple silicon:

The current M1 chip inherits a mobile-centric design built around four high-performance processing cores to accelerate tasks like video editing and four power-saving cores that can handle less intensive jobs like web browsing. For its next generation chip targeting MacBook Pro and iMac models, Apple is working on designs with as many as 16 power cores and four efficiency cores, the people said.

This makes a lot of sense; the four-port 13-inch MacBook Pro, smaller iMac and a more powerful Mac mini would all be a nice step up from the current M1 Macs.

For the highest-end Macs, the report says Apple is cooking up some truly exciting stuff:

While that component is in development, Apple could choose to first release variations with only eight or 12 of the high-performance cores enabled depending on production, they said. Chipmakers are often forced to offer some models with lower specifications than they originally intended because of problems that emerge during fabrication.

For higher-end desktop computers, planned for later in 2021 and a new half-sized Mac Pro planned to launch by 2022, Apple is testing a chip design with as many as 32 high-performance cores.

I don’t think there’s any surprise in this report in terms of CPU performance; the lowly MacBook Air is already faster than almost every Intel Mac, and as Apple moves up the Mac food chain, things are only going to get even faster.

And at the top, the best Mac I’ve ever owned, the Mac Pro.

In its current form, the Mac Pro offers eight slots of varying speed for expanding the machine with more storage, better GPUs and more.¹ However, this is not the first time Gurman has referred to the next-generation Mac Pro as being “half-sized.”

Some people have interpreted this to mean that Apple will offer a cheaper-and-smaller-but-still-expandable desktop for the first time, finally shipping John Siracua’s xMac:

My own personal conception of the xMac does not match-up well with the Mac mini. I’d go so far as to say that my xMac vision is also a lot closer to the original concept of the xMac…except I’ve already established that I’m not sure exactly where or when the xMac idea originated, so never mind.

[…]

Reduced to one sentence, it’s a completely configurable, headless Mac that trades expandability for reduced size and cost.

The xMac may indeed be the side effect of this change, but I think the reason for the Mac Pro’s future smaller form factor may come down to Apple’s GPU strategy. Here are Gurman and King one more time:

For later in 2021 or potentially 2022, Apple is working on pricier graphics upgrades with 64 and 128 dedicated cores aimed at its highest-end machines, the people said. Those graphics chips would be several times faster than the current graphics modules Apple uses from Nvidia and AMD in its Intel-powered hardware.

Many have been assuming the Apple silicon Mac Pro (and maybe other high-end Macs, like the iMac Pro) would ship with discrete GPUs from AMD, but I think that is a wish that is going to go unfulfilled. If Apple can ship GPUs that run circles around what Nvidia and AMD are doing, why would they complicate things by supporting them?

It sure seems that Apple silicon Mac Pro will have fewer expansion slots than the Intel one, which when coupled with this report, I can’t help but wonder if the MPX module has a future. Will the next Mac Pro ship with its GPU directly on the logic board, with slot-based GPUs go away altogether, just leaving slots for other things? Would it be upgradable later via a MPX module? Or will Apple divorce the CPU and GPU for maximum flexibility in a system like this, and just ship a smaller Mac Pro as it won’t need the cooling capacity of the current Intel version?²

The more we see of Apple silicon, the less confident I feel about swappable GPUs in the next-gen Mac Pro.

Whatever comes next, I’m sure some people will be happy and others will be annoyed. But that’s been the case with this machine for years, I suppose.