Introduction

Last week, Apple started shipping their new ARM M1 based Macintosh computers. I ordered a new MacBook Air and maybe I’ll get it before XMas. The demand for these new ARM based computers is high and they are selling like mad. The big attraction is that they have the computing power of top end Intel chips, but use a tenth of the power, leading to a new class of powerful laptops with battery life now measured in days rather than hours. With all the hype around the M1, people are starting to ask where Apple will go next? When will there be an M2 chip and what will it contain? Apple is a secretive company so all this speculation is mostly rumours. This article will look at my wish list and where I think things will go.

First, there will be more M1 base Macs early next year. Expect higher end MacBook Pros, these won’t have a completely new M2, more like an M1X which will have either more CPU or CPU cores and higher memory options. I expect the real M2 will come out towards next XMas as Apple prepares all their new products for the next holiday shopping season.

The Chip Manufacturing Process

The current M1 CPU is manufactured using TSMC’s 5nm process. TSMC recently completed their 3nm fabrication facility (at least the building). The expectation is that the next generation of Apple’s iPhone, iPad and Mac chips will be created using this process. With this size reduction, Apple will be able to fit 1.67 times as many transistors on the chip using the same form factor and power. Compare this to Intel which has been having trouble making the transition from 14nm to 10nm over the last few years. Of course AMD also uses TSMC to manufacture their chips, so there could be competitive AMD chips, but reaching the same power utilization as an ARM CPU is extremely difficult.

Samsung manufactures most of its chips using 8nm technology and is investing heavily trying to catch up to TSMC, hoping to get some of Apple and AMD’s business back. I don’t think Samsung will catch up in 2021 but beyond 2021, the competition could heat up and we’ll see even faster progress.

More Cores

The most obvious place to make use of all these extra transistors is in placing more CPU, GPU or AIPU cores on the chip. The M1 has 8 CPU cores, 8 GPU cores and 16 AI Processor cores. Apple could add to any of these. If they want a more powerful gaming computer, then adding GPU cores is the obvious place. I suspect 8 CPU cores is sufficient for most laptop workloads, but with more GPU cores, they could start being competitive with top of the line nVidia and AMD GPUs. The AI processing cores are interesting and are being used more and more, 

Apple is continually profiling how their processor components are used by applications and will be monitoring which parts of the system are maxed out and which remain mostly idle. Using this information they can allocate more processing cores to the areas that need it most.

More Memory

The current M1 chips come with either 8 or 16 GB of RAM. I suspect this is only a limitation of trying to get some systems shipping in 2020 and that there will be higher memory M1 chips sooner than later. For the M2 chip, I don’t think we really need an 8GB model anymore and if there are two sizes it should be 16 or 32 GB. Further, with high end graphics using a lot of memory, a good case for 64 GB can be made even for a laptop.

More and Faster Ports

The first few Mac computers have 2 USB 4 ports and one video port. There has been a lot of complaining about this, but it is a bit misleading because you can add hubs to these ports. It has been demonstrated that you can actually connect 6 monitors to the video out using a hub. Similarly you can connect a hub and have any number of ports. I’m not sure if Apple will add more ports back and either way I’m not too worried about it.

The good thing is that USB 4 is fast and it makes connecting an external drive (whether SSD or mechanical) more practical for general use. Of course making the ports even faster next time around would be great.

General Optimizations

Each year, ARM improves their CPU cores and Apple incorporates these improvements. The optimizations could be to the pipeline processing, improved algorithms for longer running operations, better out of order execution, security improvements, etc. There are also newer instructions and functionality incorporated. Apple takes all these and adds their own improvements as well. We’ve seen this year over year as the performance of the ARM processors have improved so much in the iPhones and iPads. This will continue and this alone will yield a 30% or so performance improvement.

More Co-processors

The M1 chip is more than a multi-core ARM CPU. It includes all sorts of co-processors like the GPU cores and AI processing. It includes the main RAM, memory controller, a security processor and support for specialty things like video decoding. We don’t know what Apple is working on, but they could easily use some fraction of their transistor budget to add new specialty co-processors. Hopefully whatever they do add is open for programmers to take advantage of and not proprietary and only used by the operating system.

Summary

The Apple M1 Silicon is a significant first milestone. Everyone is excited to see where Apple will go with this. Apple has huge resources to develop these chips going forwards. The R&D Apple puts into Apple Silicon benefits all their businesses from the Apple Watch to the iPad, so they are fully committed to this. I’m excited to see what the next generation chips will be able to do, though I’m hoping to use my M1 based MacBook for 8 years, like I did with my last MacBook.

If you are interested in the M1 ARM processor and want to learn more about how it works internally, then consider my book: Programming with 64-Bit ARM Assembly Language.