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Don't count on an Apple Silicon Mac Pro this WWDC

With WWDC less than a month away, we're sure to see new OS versions, but what about Apple Silicon? Let's take some educated guesses -- aka, wild speculation -- on what Apple might have in store.

WWDC (the Apple World Wide Developer's Conference) is, in theory, a conference devoted to developers. Every so often, Apple has gone off topic and used the WWDC keynote to announce something in its release docket, as it did back in 2015 when it announced Apple Music at WWDC.

The WWDC keynote, however, is most often used to introduce new features and updates to the company's various operating systems. It's a way of telling developers what features will be available to incorporate into mobile apps and desktop software applications.

Last year, the headliner was Apple's Mac transition from Intel-based processors to Apple Silicon. It's hard to believe that just a year ago, in the weeks before WWDC 2020, Apple Silicon was still just a rumor.

Wow! What a year it's been (and for once, this has nothing to do with COVID-19).

In June 2020, at WWDC, Apple announced the move to Apple Silicon. The first new-processor Macs, they said, would be available by the end of the year. Within two years, they promised the entire line would transition. The company also announced the almost immediate availability of a developer Mac mini based on Apple Silicon. Gear based on the new chip, even if limited to developers, was a surprise this early.

In November, Apple announced the M1 processor and the availability of the M1 Mac mini, MacBook Pro, and MacBook Air. With nearly identical architectures and only minor differences (plus the screen and battery on the notebooks), these were all essentially the same machine inside. Pricing was shockingly aggressive and performance, even for emulated code, was shockingly good.

In April 2021, Apple announced new M1-based iMacs (in fruity colors) as well as M1 based iPad Pro models. Tim Cook, in what seemed like almost a throw-away comment, stated that the M1 Macs are already outselling the company's remaining Intel Macs.

So, a year ago at this time, non-Intel Macs were only a rumor. Then a new processor architecture was announced, a few models were made available, they were priced very aggressively and performed like little rockets, and now, less than a year later, those models, plus new iMacs, are out-selling all the remaining Intel Macs, combined.

Comparing Mac Pro and iMac Pro to the M1

But what about the iMac Pro and the Mac Pro?

Max Tech did a comparison of a roughly $10,000 Intel-based Mac Pro compared to an $899 M1-based Mac mini. While many of the artificial benchmarks showed the Mac Pro besting the M1 Mac mini, the M1 Mac mini actually beat the Mac Pro in Safari, Xcode, and Lightroom editing (which was running under Rosetta 2 emulation).

Mac mini

What made the comparison interesting was that the reviewer said that the Mac mini held its own in actual usage, making it quite a little beast compared to the vastly more expensive Mac Pro.

View Now at Apple (2020 Mac mini)

But will there be an Apple Silicon-based Mac Pro or iMac Pro? To answer that, we need to take a minute to define what makes these Macs "Pro."

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Fundamentally, you're looking at memory capacity, network speed, processor cores, and graphics processing. The Mac Pro also adds modularity in terms of bays and slots, which allows for specialty PCI cards and accelerator cards. More on that in a minute.

When it comes to RAM, the 2019 Intel Mac Pro allows up to a whopping 1.5TB, while the iMac Pro allows up to 512GB, both vastly more that the 16GB available in the M1 Mac.

Both the Mac Pro and iMac Pro have 10GB Ethernet, but the M1 Mac mini just added that as a $100 option, so we'll call this even for all three machines.

The Mac Pro can be pushed all the way to 28 cores, the iMac Pro can go to 18 cores, while the M1 Mac mini can only go to eight cores, four of which are called "efficiency cores."

In terms of graphics processing, it's a little harder to do a spec vs. spec comparison, but we'll take a quick run at it. First, the Mac Pro can support up to 12(!) 4K displays,  the iMac Pro can support up to four external displays (in addition to the built-in display), and the M1 Mac mini can only support two. Just by way of comparison, my 2018 Intel-based Mac mini has four displays on it.

Graphics card performance and memory is a bit more difficult to manage. The M1's architecture shares system RAM between graphics and processor and is on-board, making it somewhat more efficient. That said, the total max system RAM for both graphics and processor on the M1 is 16GB, where just the graphics cards alone can go up to 64GB (the iMac Pro tops out at 16GB of video RAM).

Can the M1 scale?

So, here's the question: Can the M1 scale to Mac Pro levels? To answer that, keep in mind that the M1 is merely a branding tag associated with a particular implementation of the Apple Silicon architecture. Effectively, the M1 is the first version of Apple Silicon to be applied to MacOS machines.

Since Apple Silicon originated as an iPhone and iPad technology, its DNA is in mobile devices -- small mobile devices. As such, power management, performance, heat dissipation, and physical size were key drivers. When designing the early Apple-proprietary chips for the iPhone, nobody worried about whether you could plug in cards or drives into that architecture.

The devices being produced by Apple that sport the M1 chip are essentially the same  architecture, and this can be evidenced most convincingly in the fact that the iPad Pro and the new Macs all use the same M1 chip.

Unlike the traditional Intel desktop chip architecture, the memory for the M1 is onboard the chip.

I believe that there are two possible reasons why there is only 16GB of RAM (and limited ports) available on the M1: either (a) that was all Apple could fit on the chip given its current production capabilities, or (b) Apple was unable to get reliably high yields on chips with more RAM.

When chips are manufactured, not all chips come out with the same characteristics. It's like when you bake a batch of cookies; one or two are likely to be uglier, too hard, or too smooshy. Chips are that way, as well. The semiconductor industry uses the term "binning" to describe  how chips are divided up by their yield. Sometimes, chips that perform worse are binned as slower chips and sold as slower chips. Chips that perform better are binned as faster chips.

In Apple's case, it's possible that the machines sold as 8GB machines contain exactly the same M1 chip as the 16GB machines, but the 8GB machines didn't yield 16GB of error-free RAM.

The bottom line is I don't think the M1 can scale into the Mac Pro and iMac Pro performance heights. I also don't think the M1 was designed to allow more ports, external slots, or additional, off-chip RAM.

But what about future Apple Silicon?

In some ways, this depend on what's a priority to Apple. The M1 (and all previous Apple Silicon chips) are optimized around a single-board computer (SBC) architecture. They're not at all designed for expandability.

As such, if you're looking for a chip architecture that supports a bus designed to run add-on boards, I don't think you're going to see it anytime soon.

Instead, you might need to redefine how you think about pro-level machines. After all, Apple has already proven that, core-for-core, Apple Silicon outperforms even Intel Xeon chips. Expect future Apple Silicon chips to add more performance cores.

Apple has proven the benefits of RAM that's a pool to the entire system, so expect Apple to work towards higher RAM yields. Once the company goes all-in on augmented reality, those machines are going to need more RAM.

Likewise, Apple is going to need extreme graphics performance. The M1 chips have already shown they have substantial graphics chops, although not quite as much as dedicated GPUs. Expect that to improve in Apple Silicon.

We've been hearing rumors of an M1X or M2 chip. These could well be the same chips as the M1, but with better high quality yields, or they could be updated implementations. For sure, we'll see new versions, because Apple has been improving its silicon year-over-year for well over a decade, to a point where Apple's silicon technology is besting even industry leaders like Intel and AMD in some areas.

Expect to see something like an M-something iMac Pro well before you see a modular M-based Mac Pro. That is, if we ever see a traditional bays-and-bus Mac Pro in Apple Silicon, which is somewhat unlikely given the SBC architectural proclivities of Apple's current chip design.

As for this WWDC, it would be an ideal opportunity to introduce a second generation chip. Whether that will be announced along with a new machine is still up in the air; but if it were, expect either a Mac mini or iMac form factor, perhaps with the Space Gray "Pro" color so far missing on both M1 model categories.

What do you think? Do you think that Apple will ever create a modular M-based Mac Pro? Or do you think the future for high-performance M-based Macs will harken back to the ill-fated unexpandable "trashcan" SBC Mac Pro of 2013? Let us know in the comments below.


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