Pretty underwhelming considering the current delta between Apple’s A15 and the X2. I wonder if ARM is hampered by having to release a design that has to work on more than just the most cutting edge TSMC process.
Edit: Small miss above...Cortex-X2 dropped aarch32, though that's 2021 versus Apple doing it in 2017 with the A11, so the overall point is the same.
It was simply no market for solo aarch64 before, since a lot of costumers wanted the backup of having aarch32 compatibility.
What the article says on this topic:
"The process of eliminating 32-bit and optimizing for the 64-bit ISA exclusively has been a 2-step process. With the Cortex-X2, the underlying circuitry used for handling 32-bit architectural-related elements was removed, saving on transistors and simplifying some structures. With the new Cortex-X3, the design team took the time to start optimizing specifically for AArch64."
At some point it got twisted into "double the speed", but Moore's Law as originally formulated was precisely about this - doubling transistor count.
Disclaimer: Not an EE / HW designer. Going off of memory from tech news + some university courses (info may be incorrect / stale).
I was seriously considering being a chip engineer for a while and did my master's thesis on adder design.
They're constrained by what their customers want. Yes it's nice to have the highest performing chip but plenty of space in the mobile market for less than best CPUs. Anyone buying arm CPUs doesn't have the A15 as an option so in a sense it's not a competitor. Someone selling premium phones is trying to out-compete apple but how much does the raw performance stats matter to the consumer markets?
I think there's also a tendency for everyone to want to do their own CPU now. Qualcomm and Samsung might want their arm micro-architecture to be the A15 killer and only buy the lower performance cores off arm for instance.
I wonder how many of these are actually vanity projects? Apple spent billions for more than a decade on ARM development before using their own design as a central processor.
OTOH MediaTek et all don’t worry about any of that.
For their computer platforms. Apple has been using ARM since the Newton.
Anyone who wants to differentiate from competition building x86 boxes will have to use a non-x86 design. Viable ones these days are mostly POWER for workstations and servers, and ARM for everything between mobile and midrange servers.
If you build a commodity computer based on the same components everyone else has access to, your margin will be squeezed. If your product has different characteristics than your direct competition and that difference is advantageous on a given segment, your competitors will have trouble moving in. That's why Apple M-series and IBM mainframe CPUs are not available to anyone without a full computer attached.
The Newton used a regular ARM design (that was back when Apple owned a huge chunk of ARM). They used 3P ARMs for the main processor of other devices for years (e.g. time capsule or some video dongles).
That one sentence of mine you referred two made two points: 1 - it took a long time for apple to get to the point where they could replace external designs as the core processor for a device (starting with the phone) and 2 - that they had by that time quite a bit of experience for using their own designs for subsidiary processors inside their devices. All of that is a pretty complex undertaking.
> If you build a commodity computer based on the same components everyone else has access to, your margin will be squeezed. If your product has different characteristics than your direct competition and that difference is advantageous on a given segment, your competitors will have trouble moving in.
Well, it’s all about where your locus of differentiation is; all else you want to commoditize. It’s not like Apple makes their own DRAM, and those suppliers are the ones that get their margins squeezed (especially by Apple — look at who their CEO is).
And the lack of a CPU design team is a competitive advantage for the MediaTeks of this world, even if it’s not exclusive to them. Instead the very lack of exclusivity in cpu has a network effect value for them. This is what killed arm competitors like MIPS.
In 2008 Apple acquired PA Semi and two years later they released an iPad powered by the A4, their first in-house design. Many acquisitions and designs later, their performance started to approach the performance of Intel chips used in their desktops and laptops. It was a very complex undertaking and they nailed it on every step.
All Apple computer ISA transitions were driven by external factors. Motorola gave up on the 68K family (a dead end for them) in favor of the 88K RISC processors (where they thought they had a chance), Motorola and IBM gave up on PPC and never delivered a low power G5 (they offered Apple Cell instead). Finally, Intel didn't give Apple the special treatment it needed to differentiate from other laptops and, since by then Apple had phone and tablet SoCs that were competitive with Intel parts and there was lots of commonality between macOS and iOS, that last choice was easy. Depending on a third party for the component more easily usable to set you apart from your competition is never great. If Apple moves their Macs and mobile devices away from ARM, it'll be the first time Apple decides that without a "catastrophic" event from outside.
As a company, they don't like being at the mercy of someone else if they can help it.
True. Up until now, it was always betting the company on someone else's silicon roadmap. Now they control it completely.
I mean... I think it's the opposite. There was a time when Qualcomm, Samsung and Nvidia had their own microarchs which they used in most things. Increasingly they're back to ARM-supplied designs now.
I suspect this is partly because the ARM designs are adequate these days, but also because phone CPUs just aren't that competitive anymore; the iPhone is enormously faster than any other phone, and consumers do not care about this at all, because the other phones are, generally, Good Enough.
Indeed but I'm wondering if we'll see a swing back, if they're all selling SoCs with the same set of arm IP in varying configurations what's the differentiating factor? I suspect there's an aspect of 'arm never builds what we want' as arm needs to satisfy multiple people that would drive them to build their own design at the high end. That said I've only got a hunch and can't recall concrete evidence for this.
It seems to me like modern core design is expensive and high risk/low reward for most of these companies. Remember, Apple has a ton of R&D and the margins to put massive cores into just about everything they sell, upto and including putting a CPU faster than most desktops into their "budget" monitor. Fabbing costs keep going up and the extra revenue from larger+faster CPUs would get gobbled up by TSMC and Samsung Fab. Setting out to build something faster at the same size and R&D is what eats your profit.
For Qualcomm, Samsung, Google (for Pixel at least), and NVidia, ARMs balance of performance/die size/efficiency is aligned well with their market positions and the opportunity cost of rolling their own is just too high even in the face of thinning margins from competition.
“ The End of the Road for General Purpose Processors & the Future of Computing - Prof. John L. Hennessy”
https://www.csail.mit.edu/news/end-road-general-purpose-proc...
[1] https://www.extremetech.com/computing/319968-google-microsof...
See monocasa's comment.
And the reason that I'm assuming that no one else has the same 'special relationship' is that it's a not well kept secret that Apple designed large parts of the base AArch64 with ARM and simply owns the IP on large parts of the ISA, similar to how at this point both AMD and Intel practically own x86 due to their different contributions over the years. Qualcomm, et al can not say the same.
Anyway, I think my comment is still valid.
The "special relationship" is just fanboy fantasy. Qualcomm and Marvell have both in past done ground up designs that significantly differs from any ARM silicon.
If you don't believe me, fell free to provide actual proof of this special license.
Particularly the new instructions are damning as ARM has said they are specifically disallowing custom instructions this go around in order to combat architecture fragmentation.