Apple Silicon, some speculation

Some musings on what we might see from Apple in 2021.
When Apple Silicon was released, it impressed with both its power, and its power efficiency. Here was a system that matched or exceeded the current Apple MacBook Pro and MacBook Air capabilities, but with vastly superior battery life. And, because of Rosetta 2, it even ran existing Intel 64bit code—and astonishingly, did so as fast, or even faster than equivalent Apple Intel models.

Now, there are some caveats on all of the above. There are some things the current M1 SoC doesn’t do as well as the old systems:

  • Maximum of 16GB of memory, with no upgrades possible.
  • Only built-in graphics, no support for external graphics.
  • Only two displays supported. Either the built-in display, plus one external for laptops, or two external monitors for the Mac Mini (cf 3 monitors in current systems)
  • Doesn’t run Windows
  • Doesn’t run other Intel operating systems in a virtual machine

Memory

The memory looks at first rather like an “Apple Tax”, with the memory soldered to the motherboard. You can’t add extra memory DIMMS later. As computer memory is a highly commoditised item, this means you pay more—sometimes considerably more—for memory.

However, this “Unified Memory” as Apple refers to it, has considerable advantages over DIMM memory. Putting the memory on the main chip leads to much greater bandwidth, and much lower latency, which obviates the need for dedicated graphics memory. Normally, using shared graphics memory is a performance compromise, lower cost but lower performance—not so with Unified Memory.

This sounds fine, but creating a chip with lots of specialised units (CPUs, Neural engine, GPUs, Networking) and lots of plain old memory (a memory cell, multiplied by several billion) sounds a bit problematic.

Then, I saw photographs of the SoC and the penny dropped. The SoC is not one chip, it’s  two silicon chips joined together on a carrier. One half (well, closer to ⅔) is what I’ll call the CPUs, for simplicity’s sake. The other is plain old memory.Apple M1

And thinking about that leads to speculation about the next systems to come from Apple, and what capabilities they might have.

The Shape of Things to Come

Firstly, let’s consider the Apple product line, excluding iPhones, wearables and HomePods.

  • MacBooks (plain, Pro and Air)
  • Mac mini
  • iMac
  • Mac Pro
  • Apple TV

Of those, only the first two categories were released with Apple Silicon. That makes sense, since the Mac mini is essentially a laptop without a screen, so really the M1 was released for Apple’s laptops with the Mac mini coming along for the ride.

The Apple TV already uses an ARM chip, so it’s really an iPhone without a screen (more nearly, an iPod without a screen). It’s been years since the last Apple TV upgrade, so arguably it’s due a refresh, but there is probably no hurry compared to the iMac and Mac Pro.

So, let’s look a little closer at the M1 SoC and see what its strengths and weaknesses are:

Strengths:

  • Unified memory
  • Thunderbolt & USB with dedicated controllers per port (current Mac models share a controller between two ports)
  • 4 high performance cores
  • 4 high efficiency cores
  • An 8 core GPU that matches bottom end discrete GPUs

Weaknesses:

  • 16GB memory max
  • Supports only two displays
  • No eGPU support

The eGPU support is almost certainly simply a lack of ARM64 drivers, and so can be fixed with a software upgrade, which I’m betting will happen.

I’m also betting the current M1 SoC chip design doesn’t allow for more memory.

So, any future M1 upgrades might be a little faster (higher clock rate, or other internal tweaks), in an M1X or similar, but are unlikely to have more cores or a vastly faster GPU.

What does that mean for future models?

There may be more laptop releases in 2021 using an M1 or ‘M1X’ with better specs, but they won’t support more displays, more memory, or more CPU cores.

Unified Memory

Unified memory isn’t going away. There won’t be any Apple Silicon models released with support for SIMMs, not even on the MacPro. The latency and bandwidth advantages are just too big.

However, given that half (⅔) the M1 is RAM,

M1

you can easily see the RAM doubling (RAM on both sides, with the processor chip a sandwich in the middle),

M2 with 32GB

or quadrupling with RAM top and bottom as well,

M2 with 64GB

or even eight times, with the RAM entirely encircling the CPU.

M2 with 128GB

So the next system will probably support 32GB, with 64GB and 128GB a possibility. Not bad, but still not up to the 1.5TB supported by the current Mac Pro.

CPU

All that RAM needs something to use it, so a bigger chip is likely to have more high performance cores, probably retain the 4 high efficiency cores, but with 6, 8 or 12 high performance cores

GPU

The next system will almost certainly support 3 monitors, maybe four.

I imagine that Apple is working on GPUs that are at least twice as powerful as the M1, and on support for eGPUs of course.

Windows and other guests

That leaves the problem of running Windows as a guest operating system, or emulating Intel code well enough to run other operating systems.

Since Microsoft has a version of Windows that runs on ARM64, we will see virtualisation solutions such as Parallels or VMWare that run virtual machines, but for ARM64 guests.

Windows also has its own emulation software that works like Rosetta, emulating x86 on ARM. That means there should soon be an acceptable solution for Windows 10, Linux, BSD and other operating systems that have native ARM64 support.

CodeWeavers have announced CrossOver support for Apple Silicon, which is an alternative solution.

However, that leaves x86 code for older versions of Windows, and MacOS, for those who want or need to keep running such things, and for whom virtual machines have been the perfect answer. The response to this is unclear, but there is probably a lot of work going on right now to get x86 emulators on ARM64 up to speed (or possibly licencing one of the existing ones).

Speculation

So, what are we going to see released in 2021? Based on the above, here are my predictions for the next wave of Apple Silicon.

Probable

The next model to be upgraded (not counting M1X speed bumps for the laptops) will be the iMac, with an ‘M2’ chipset.

  • 12 CPUs (8 high performance and 4 high efficiency)
  • a GPU with double the current performance (16 cores)
  • Support for at least three monitors (built-in plus two more)
  • Support for external GPUs
  • Memory will go up to a maximum of 64GB, possibly 128GB.

Possible

  • Possibly a low-end Mac Pro with 12 cores and 128GB will also be announced.

Unlikely

  • The full-noise Mac Pros will await the ‘M3’, in 2022.
  • The Apple TV might get a refresh, but it won’t need any of the power of the M2 and beyond SoCs.

Disclaimer

I’m just speculating, from a little country half a world away from Cupertino (literally, half a world away). I don’t imagine the actual specs will be much less that that, but I would not be thunderstruck to find that the Apple engineers have something even more impressive waiting in the wings. I guess we’ll just have to wait and see.