While rumors of Apple moving away from Intel CPUs for Macs have spread for years, they are especially vivid around WWDC 2020. In the following, I’ll explore the transition of the Mac away from Intel. The benefits of doing so, as well as options and obstacles Apple would face in their third CPU transition since 1992.
Most speculations revolve around moving Macs to Apple’s own A series ARM–based CPUs and for optimal performance, developers would be required to recompile their existing software. Hence bringing developers on board at this year’s WWDC ahead of making new architecture Macs available to the broader public. But what about software that cannot be updated in time or at all?
To emulate – or not?
In the past, Apple used emulation to make CPU architecture transitions transparent to its users. [1] [2] Where the instruction set of one CPU is translated in software to the other. Though, emulation usually is a costly process and as such requires much higher processing power on the host CPU. In Apple’s 2005 transition, Intel’s leap in performance over PowerPC, among other optimizations, made this feasible.
Since Desktop CPUs can leverage much higher power consumption over mobile chips to drive performance, the general assumption of a performance gap held true for most of the past. Nonetheless, with Apple’s year over year performance gains in their A series chips and Intel’s lack of keeping up theirs, Apple today has mobile chips that go head to head or surpass Intels Desktop CPU offerings. At least for day to day computing needs. [3]
Now, is this performance adequate to drive an emulation layer without introducing a user noticeable performance loss? From the vast experience with emulation, one would assume not. Indeed Microsoft has introduced an ARM–based x86 emulation with Windows on ARM. The restrictions of only emulating 32–bit apps and the performance are a bleak outlook (pun intended).[4] Interestingly Intel seems to be on the fence about this. [5]
But it’s 2020 and today more than ever before Apple is a chip designer. Unlike in the past, they are not switching to another vendor’s CPU. They’re designing CPUs to their specific needs and over the past decade, this has resulted in what is today a flagship mobile CPU. [6]
Hardware support for emulation?
Can Apple’s experience in CPU design entertain the thought of adding hardware features that speed up software–based emulation? Apple’s ARM Architecture License certainly allows them to expand its Instruction set. And who knows maybe an x86 license agreement came included with the one billion dollar deal of Apple’s acquisition of Intel’s modem division in 2019. [7]
Hardware–based emulation is certainly not unprecedented as Transmeta has produced such CPUs in the past. According to Wikipedia Transmeta’s IP is licensed by Intel, nVidia, Sony, Fujitsu and NEC. Interesting nevertheless. [8]
Would you like some GPUs with that?
Although I’ve focused solely on the CPU I’d expect Apple to expand their powerful GPUs to the Mac as well. Something makes me believe that the conception of the Metal API on the Mac is a long year plan finally coming together. All recent Mac Laptops have relied on the integrated GPU options from Intel. While high-end models offer discrete GPU options, they have been AMD only for years. Whatever the beef with nVidia — it’s ridiculous for us users to be at the end of this feud. So yeah, the more options the better.
What about the Pro’s?
Current high-end models of iMac Pro and Mac Pro are available with up to 28 CPU cores. And creative professionals can make use of every single one. In contrast, the most current A12Z CPU in the iPad Pro features eight cores at max, while only 4 of those are high performance. It is unclear to me what Apple could offer in this regard. AMD has recently released a 64-core monster of its Threadripper CPU, a dream come true for all of us doing heavy multi-core computing. I don’t see Apple entering this arena any time soon.[9]
The long run
But what’s the long term benefit of moving the Mac to ARM? One would be control of the ecosystem. With Intel’s inability to deliver better performance with its Core architecture, Apple is better off by taking CPU design in-house. They would be in the same place as with iOS devices and they certainly are and have been in a great place. Another is better performance per watts. Something that was touted during the PowerPC transition. The A series chips deliver outstanding performance while using much less power at the same time. Future Mac laptops should have longer battery life if iOS devices are an indicator, all while needing less energy overall. Inarguably a good thing for users and the environment.
While I loved my Quadra 610 with its beefy 68040, it paled in comparison to the PowerMac 7100 that replaced it in 1994. The same goes for my Titanium PowerBook G4, which made way for a MacBook Pro in 2006. With the Mac back on regular updates, I am excited today as I was back then. The past CPU transitions were beneficial to me as a user. It empowered me to venture into new computing areas – and that is a great thing.
The speculation of Apple’s move away from Intel is years old – and for Intel, the writing has been on the wall. As the A series are mobile CPUs, I’d put my money down, that the first ARMed Macs will be laptops. The benefits of performance gain and power savings are front and center. We’ll know more on June 22nd.