[HN Gopher] Arm Unveils Next-Gen Flagship Core: Cortex-X3
       ___________________________________________________________________
        
       Arm Unveils Next-Gen Flagship Core: Cortex-X3
        
       Author : rbanffy
       Score  : 132 points
       Date   : 2022-06-29 11:06 UTC (11 hours ago)
        
 (HTM) web link (fuse.wikichip.org)
 (TXT) w3m dump (fuse.wikichip.org)
        
       | pclmulqdq wrote:
       | This is still a mobile chip. The real "flagship" cores should be
       | in the Neoverse line.
        
         | Veliladon wrote:
         | Neoverse is a mobile chip based on putting massive amounts of
         | aggregate power vs die area. It's not a flagchip architecture
         | because it's very conservative as far as execution goes. It
         | just lumps stacks of cores on a single die and lets the
         | OS/workload dictate the performance.
         | 
         | In comparison an X3 is a much faster chip clock-for-clock per
         | watt on a per core basis because it's built for ultimate ST
         | performance on a power budget. X3 has a full 6-way decoder vs 4
         | on Ares. So straight off the bat you can decode 1.5x as many
         | instructions. X3 has a 320 entry ROB vs 128 on an N1 so you can
         | keep over twice as many instructions in flight. An N1 has 3 ALU
         | pipes, an ALU with MAC and DIV, and two FPU pipes. X3 on the
         | other hand has 4 ALU, an ALU/MUL pipe, and an ALU/MAC/DIV pipe.
         | On the FPU side it has two FMAC pipes and two FDIV pipes.
         | 
         | The X3 is a much larger and more powerful core than an N2
         | little alone an N1 and deserves to be called a flagship core in
         | every sense of the word.
        
       | [deleted]
        
       | kramerger wrote:
       | Everytime CPU stuff is discussed it is quickly hijacked into
       | praising Apple.
       | 
       | Can we have a discussion about this CPU instead of talking about
       | others? M1/M2 are not even the current top performing CPUs...
        
         | babypuncher wrote:
         | Probably because the M1/M2 are kings of the roost as far as
         | consumer hardware goes. No consumer ARM chip comes close, and
         | Intel needs 3-4x more power draw just to match Apple on
         | performance.
         | 
         | The M1 is the stick by which all new ARM chips are going to be
         | measured for a while.
        
         | tensor wrote:
         | Discussing chip design in contrast to other chips is useful for
         | discussion.
        
         | chasil wrote:
         | "Perhaps more critically, the new core offers exclusive support
         | for only AArch64 - dropping 32-bit support altogether."
         | 
         | I don't understand why ARM wants to throw away
         | AArch32/Thumb/Jazelle et al.
         | 
         | This really shouldn't be in a phone - a lot of Android apps
         | bundle 32-bit binaries for various purposes, and they won't run
         | on this CPU.
         | 
         | I can see why Fujitsu mandated AArch64, but my phone isn't
         | going to be on the Top 500, and there were benefits to these
         | old instruction sets.
        
           | imoverclocked wrote:
           | There are also benefits to cleaning up silicon. Eg: less
           | transistors per core can mean more cores or less power or
           | both.
        
             | chasil wrote:
             | If this were the case, then it would be better still to
             | design a totally new instruction set.
             | 
             | Why cling to any remnant?
        
               | msbarnett wrote:
               | AArch64 is, effectively, a totally new instruction set.
               | It was designed to allow for fully regular decoding,
               | unlike AArch32 & Thumb, which is a big part of why
               | getting those off of the chip is a big win - it's not
               | just the decoders you clean up, you can now make your
               | pipeline and speculation deeper because you can peek N
               | instructions into the future without having to decode the
               | N-1 instructions in front of it first to figure out where
               | the Nth instruction lies. That's part of why you see
               | AArch64-only designs like this and the A12+ cores with
               | much larger reorder buffers.
        
             | [deleted]
        
           | rbanffy wrote:
           | Binary compatibility is no longer a huge concern. By now only
           | very old programs will require arm32 support and most current
           | offers on any app store will have been recompiled for the
           | latest and greatest (because software writers also want to
           | look better on newer CPUs). Plus, if the new hardware is that
           | much faster, you may not even need to pack native blobs.
        
             | chasil wrote:
             | Of the Raspberry PIs, only the 3rd generation is capable of
             | AArch64.
             | 
             | Because of this, very few Linux distros supporting the PI
             | are 64-bit (Oracle Linux is the only one that comes to
             | mind).
             | 
             | There does indeed remain a large AArch32 community that
             | cannot move, and they will never, ever cross this gulf.
        
               | rbanffy wrote:
               | A new chip not supporting arm32 does not prevent software
               | for being built for the platform. While there are enough
               | users, the distros will be maintained.
        
             | ncmncm wrote:
             | Emulation ought to suffice for support of programs compiled
             | for 32 bits.
        
         | iasay wrote:
         | You're right but they are the only ones shipping in something
         | that isn't a turd.
        
         | MuffinFlavored wrote:
         | > M1/M2 are not even the current top performing CPUs...
         | 
         | What are?
        
         | monocasa wrote:
         | They're the top performing Arm CPUs.
        
           | homerowilson wrote:
           | Maybe? There exist some extreme-performance ARM CPUs like
           | A64FX from Fujitsu.
        
             | monocasa wrote:
             | I would be shocked if an A64FX core could go toe to toe
             | with a Firestorm on general code. It just doesn't make
             | sense for Fujitsu's use case to spend nearly as many gates
             | on general improvements versus more vector ALUS.
        
             | rbanffy wrote:
             | They are the top performing ARM computers you can go to a
             | store and buy. I'd love to have an HPE Ampere or a POWER
             | tower under my desk, but it's not easy to get anything like
             | those, and certainly not for a price competitive with
             | generic x86.
        
               | NikolaNovak wrote:
               | Are we confusing things?
               | 
               | They're both RISC, but P9/P10/etc is based on IBM's own
               | Power microarchitecture (possibly open sourced / open
               | standard), I wasn't aware it had anything to do with Arm?
               | I could be hopelessly wrong...
               | 
               | Or do you mean something different with "POWER"?
        
               | rbanffy wrote:
               | There are other interesting ISAs that are not arm64.
               | Sadly, the only ones that still could be viable desktop
               | (more like deskside) are either server-grade ARM or IBM's
               | POWER (and none of them makes Mac Minis).
        
               | mhh__ wrote:
               | Owning an IBM Power system is a daydream of many nerds
               | apparently.
               | 
               | And power is open in that the ISA is open. Power10 is a
               | bang up to date CPU so the internals are all closed.
        
             | mhh__ wrote:
             | The A64FX is a very specific microarchitecture that's aimed
             | at big core counts rather than being a single threaded
             | monster.
        
         | akmittal wrote:
         | I hate Apple for lots of things. But they have done exceptional
         | work with M1/M2. Imagine that power efficiency on servers.
         | Saving so much energy.
        
           | grumpyprole wrote:
           | It is exceptional work, but the system-on-a-chip design is a
           | form of compromise, especially with regard to the
           | availability and pricing of RAM configurations. The current
           | MacBooks ship with the same amount of RAM as my Android
           | phone.
        
           | rbanffy wrote:
           | > Imagine that power efficiency on servers. Saving so much
           | energy.
           | 
           | There's no magic in those chips. Power efficiency is a design
           | parameter you may optimize for or not, and ARM server chips
           | dissipate more power because they have a lot more cores, more
           | memory controllers, more cache, more IO, and, in general, a
           | lot more stuff than a personal computer CPU would make sense
           | to have. Computation per computation, they are not far from
           | each other.
           | 
           | Intel's x86 ISA mandates a more computation to happen per
           | amount of useful computation served - lots of memory write
           | reordering, lots of instruction alignment (instructions can
           | have from 1 to 15 bytes, IIRC) and other operations that do
           | not translate into anything useful for the user beyond a
           | higher IPC if your instruction stream is just right, but,
           | also dissipate a lot of power for that.
        
           | izzydata wrote:
           | But is Apple ever going to allow their CPUs to be used for
           | anything other than their own products? If it isn't even an
           | option then it is mostly irrelevant. I can't get a Windows
           | laptop with an Apple M2 so it isn't worth checking how
           | efficient of a CPU it is compared to Intel and AMD.
        
             | Sakos wrote:
             | My workplace gave me a choice between an M1 Macbook or an
             | Intel-based Lenovo. Even though I'd never used a Mac full-
             | time before, it was a no-brainer and I picked the Macbook.
             | It absolutely does matter.
        
             | klelatti wrote:
             | Actually it's not irrelevant. Lots of people choose between
             | a Mac and Windows and the M chips up the competitive
             | pressure on Intel and AMD to improve their offerings.
        
           | GeekyBear wrote:
           | Dropping the M2 into the same entry level Macbook Pro they
           | sold last year gains you a couple of hours of battery life as
           | well as a performance increase.
           | 
           | https://www.tomsguide.com/opinion/macbook-
           | pro-2022-battery-l...
           | 
           | That's pretty impressive for staying on the same process
           | node.
        
             | ceeplusplus wrote:
             | That battery life test is understating the advantage Apple
             | has over x86, probably because it's idling too much. The
             | gap in a more CPU intensive web browsing test is more like
             | 2x more than competing x86 ultralights [1].
             | 
             | [1] https://www.notebookcheck.net/Apple-MacBook-
             | Pro-13-2022-M2-L...
        
               | [deleted]
        
             | akmittal wrote:
             | Truly amazing, most people (including me) thought after M1
             | perf gains will be marginal
        
         | undersuit wrote:
         | When I first loaded this article your comment was on top and
         | had no comments. It's still on top and the comments are talking
         | about M1/M2. You applied the Streisand Effect to yourself.
        
         | mhh__ wrote:
         | Top performance CPUs in whose laptops?
         | 
         | My alder lake is faster than an M1, my alder lake needs 4 fans
        
         | akmittal wrote:
         | I feel Mobile CPUs are fast enough from last 5-6 years. Its the
         | battery tech which is lagging.
         | 
         | On Laptop/Server side Qualcomm need to catch up to AMD/Apple.
        
           | usrn wrote:
           | After my experiences with Android I will never ever buy
           | another device with a Qualcomm SoC again.
        
             | arifmeticus wrote:
             | Could you explain why?
        
             | akmittal wrote:
             | I had totally different experience, One i bought with
             | Exynos was Battery hog, Mediatek ones generally have bad
             | performance.
        
             | danielEM wrote:
             | I'm also curious what were your experiences with android
             | that were affected by Qualcomm?
        
               | uni_rule wrote:
               | Maybe they had an 810 crap out on them
        
             | rbanffy wrote:
             | After my experiences with Android, it'll be really
             | difficult to make me buy an Android phone.
             | 
             | Compared to iOS, everything is slightly clunkier.
        
               | karamanolev wrote:
               | I'll take "slightly clunkier" before "extremely locked
               | down and limited in unthinkable ways" any day, and not
               | just for Android, but in general.
        
           | frostwarrior wrote:
           | IMHO that's because Apple was the first to bother optimizing
           | an ARM CPU for performance instead of battery life.
           | 
           | The performance per watt in ARM exceeded x86 since long ago,
           | but most manufacturers used that feat to create mobile CPUs
           | instead of cranking up the power to see if it catches up to
           | high performance x86
        
             | akmittal wrote:
             | I think reason is that Qualcomm need to sell to Phone
             | makers so they can't make their SoC very expensive.
             | 
             | On the other hand Apple can make expensive SoC without
             | worrying about sales
        
               | PaulHoule wrote:
               | Apple has a big advantage over Microsoft in terms of
               | building PCs.
               | 
               | Apple can decide that it is switching from Intel to ARM
               | and not looking back so it not only realizes costs from
               | investing in ARM but it ultimately will realize savings
               | from not having to support Intel.
               | 
               | There is no real unity behind Microsoft, Dell, Lenovo and
               | all the other vendors, plus the motto of Windows users is
               | "who moved my cheese?" You don't use Windows because
               | Windows is the best operating system, you use Windows
               | because it has the most software, and that software is
               | written for and optimized for the x86 platform. Microsoft
               | is always floating ARM-based systems as a hobby but it
               | cannot make the commitment that it is going "all in" so
               | it has to support Intel as the primary processor for the
               | foreseeable future, so the ARM transition costs Microsoft
               | but never saves them anything.
               | 
               | On top of that Microsoft is dependent on vendors like
               | NVIDIA and AMD to supply drivers for graphics cards and
               | all the other parts for their machines and getting them
               | all to supply good drivers for ARM is yet another big
               | ask. Apple can say "here is the supported hardware" and
               | not have to fight with vendors who have the power to
               | torpedo their ambitions.
        
               | K0SM0S wrote:
               | Thank you for a rather enlightening perspective. That
               | explains a lot of big tech behaviors around the x86/ARM
               | frontier that I had failed to grasp.
               | 
               | I find it somewhat ironic that in wanting for a few CEO's
               | to _" Embrace... Extinguish"_ Linux in favor of Windows,
               | Microsoft eventually created a world where Windows is a
               | sink on their resources they yet can't axe because though
               | not anymore a money-maker in its own right, Windows
               | remains the basis for pretty much all their money-makers.
               | In becoming a "software-first" company, they pretty much
               | followed if not provoked the very paradigm that makes
               | Windows a non-monetizable entity next to as-good-as-
               | embedded MacOS and ever-free Linux.
               | 
               | Linux which, incidentally, is also THE basis for money-
               | makers worldwide and the OSS model means nobody using it
               | today had to fork even 1% of the real cumulative cost of
               | that kernel + ecosystem since the 1990's. How's that for
               | a win, _Linux 1:0 Microsoft_ -- that the winner did not
               | even seek, busy doing its own thing, while the other
               | pretty much dug its own commercial grave out of
               | 'relevance debt' (not sure how to word what Windows has
               | become)...
               | 
               | TL;DR: it's like this big item taking all your inventory
               | yet that you can't ditch _ever_ because it 's required to
               | do all your quests. In games, you wish devs forgot about
               | that crap and just made the inventory that much smaller.
               | In real life, Microsoft can't kill Windows without
               | closing business overnight. sad_pikachu_face.jpg
               | 
               | [Note that IMHO, MS is incredibly strong nowadays, so
               | they'll find a way, and this is a fantastic learning
               | experience for the industry.]
        
               | _ph_ wrote:
               | At minimun, Microsoft could try for real. In 2019 Samsung
               | announced the Galaxy Book S with an ARM processor. Looked
               | like a nice compact laptop. I would have been interested
               | in it, but it was basically never available and limited
               | to Windows for ARM. Which isn't even officially sold by
               | Microsoft, you can run it fine on the new Macs in a VM,
               | but only as a part of the beta test access. Even if
               | Microsoft cannot force the whole market to ARM - and
               | might not even desire to do so - at least they could
               | treat Windows 11 for ARM as a full product.
        
               | bombcar wrote:
               | If Microsoft wanted to really try an ARM push they could
               | do worse than releasing a Surface laptop _with amazing
               | out-of-the-box Linux support_ ; it might not sell a ton
               | to Windows users, but they could get something moving.
        
           | rawoke083600 wrote:
           | Speaking of battery-tech and mobile. I wish I can get "today
           | phones" but with a "thick option". i.e add 2-3mm in thickness
           | for greater battery capacity ?
        
             | windowsrookie wrote:
             | Apple has made the last few generations of iPhones thicker
             | to do exactly that.
        
             | semi-extrinsic wrote:
             | How much do you want? Motorola has a couple of 6000 mAh
             | battery options, and I think even Samsung has a few 5500
             | mAh models.
        
           | danielEM wrote:
           | Yes, they are so fast that I would be happy to use my phone
           | as a computer if the industry didn't make it close to
           | impossible
        
             | 2Gkashmiri wrote:
             | try to use ffmpeg on termux and on a regular laptop. beyond
             | some slight timing difference, my tests on a random file
             | gave me similar results which is amazing
        
             | MR4D wrote:
             | My gut tells me that if we could, there would be phones
             | catching on fire all over the place.
             | 
             | Although a phone has tons of power, and can probably
             | function as a low-end desktop, the lack of a sizeable
             | cooling solution, or even just a plain heatsink, would
             | cause it to throttle pretty quickly.
             | 
             | I have to believe this is the reason, or otherwise someone
             | would have done it already (successfully that is) for such
             | an obvious use case.
        
       | aszantu wrote:
       | Missed opportunity to call it coretex
        
         | rekoil wrote:
         | Core-Tex(tm)
        
           | mayormcmatt wrote:
           | Don't mess with Core-Tex.
        
           | frostwarrior wrote:
           | 8 High performance CoreTex cores and 2 low performance
           | CoreMex cores
        
             | phlipski wrote:
             | CoreChex - for that extra crunch!
        
         | johnebgd wrote:
         | Intel would file a "crash" lawsuit.
        
       | varispeed wrote:
       | They could call it Cortex-Vapour. I mean very much every popular
       | MCU is out of stock anywhere. Throwing new cores into broken
       | market will only exacerbate problems - the production lines will
       | be clogged by new cores while businesses still wait for the older
       | cores.
        
         | picture wrote:
         | Here lies an unique property of semiconductor fabrication:
         | unlike other resources like grains where you can just feed in
         | different raw materials to a factory and get your desired
         | output, it is very difficult to reconfigure a fab workflow to
         | use even a slightly different process, and downright impossible
         | to switch between generations (5 nm to 22 nm) without near
         | complete replacement of every equipment.
         | 
         | You won't be able to directly increase production of what's
         | actually really hard to get at the moment (microcontrollers and
         | small functional devices using "ancient" process nodes) by
         | decreasing production of cutting edge processes
        
       | kache_ wrote:
       | Cooler. Faster. This is the decade of low wattage CPU chips :)
        
         | rekoil wrote:
         | Finally. CPUs have been _fast enough_ for a while now, about
         | time the industry starts pushing efficiency and battery life
         | instead.
        
           | jbverschoor wrote:
           | Not if you ask electron devs
        
             | mech422 wrote:
             | Gotta admit that made me snort :-D
        
             | rekoil wrote:
             | Shiiiiet. :(
        
             | rbanffy wrote:
             | For them, memory volume and bandwidth are probably more
             | important than single-thread performance.
        
               | sceadu wrote:
               | emacs - electron making apps constantly swap
        
       | rayiner wrote:
       | 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.
        
         | pjmlp wrote:
         | Given that Apple's CPUs aren't available in cloud deployments,
         | I couldn't care less other than when doing iDevices projects.
        
         | ksec wrote:
         | ~20% Pref Increase ( Clockspeed + IPC ) gives you a Single Core
         | GB5 score close to A14. Considering the transistor and power
         | budget, and the IP cost of X3 I actually think this is pretty
         | damn impressive.
        
         | mmastrac wrote:
         | Apple has an architectural license that allows them to build
         | their own compatible processor [1] purely targeted to what they
         | need.
         | 
         | [1] https://www.extremetech.com/computing/319968-google-
         | microsof...
        
           | MikusR wrote:
           | So does Applied Micro, Broadcom, Cavium, Huawei, Nvidia, AMD,
           | Samsung, Marvell, Microsoft, Qualcomm, Intel, Faraday
        
             | monocasa wrote:
             | Apple has something deeper than the architectural license
             | the others listed have. They've gone further with changes
             | than others are allowed to.
        
               | kramerger wrote:
               | This is not true.
        
               | monocasa wrote:
               | Which part? I could come up with a half dozen ways off of
               | the top of my mins that the M1 cores don't comply with
               | the Arm ARM. Not being able to turn of VHE in EL2 is one
               | example. And Arm has stated widely that architectural
               | license holders have to comply with the Arm ARM still.
        
               | kramerger wrote:
               | You are assuming that no other company has this type of
               | license or has done this type of architectural changes.
               | That is not true.
               | 
               | See monocasa's comment.
        
               | monocasa wrote:
               | I am monocasa; that was my 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.
        
               | kramerger wrote:
               | Huh, I meant MikusR :(
               | 
               | 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.
        
               | pertymcpert wrote:
               | I've yet to see QC add custom instructions to their
               | cores.
        
               | monocasa wrote:
               | It's been posted elsewhere, diverging from the ARM
               | Architecture Reference Manual in ways that other chips
               | have not. New instructions in spaces like ML,
               | decompression, new privilege modes, features that are
               | fixed on that are specficed to be optional at runtime,
               | etc.
               | 
               | 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.
        
               | kramerger wrote:
               | https://www.arm.com/technologies/custom-instructions
        
               | monocasa wrote:
               | If you read that link, it's specifically for ARMv8-M
               | microcontroller class cores. ARMv8-A has no similar
               | program.
        
               | MikusR wrote:
               | I have seen comments saying that but no sources.
        
               | monocasa wrote:
               | It's widely been stated including by Arm that
               | architectural license holders must still fully comply
               | with the Arm Architecture Reference Manual. Apple's Arm
               | cores do not.
        
               | dagmx wrote:
               | In what way are they non conforming?
        
               | monocasa wrote:
               | Dozens of different ways. New instructions, new privilege
               | modes, VHE mode in EL2 can't be turned off, etc.
        
               | msbarnett wrote:
               | Obviously some of those are intentional architectural
               | deviations, but is there a good reason to believe the
               | stuck HCR_EL2.E2H bit isn't just an errata?
        
             | jeffbee wrote:
             | AppliedMicro's architectural license is now held by Ampere.
        
         | Octoth0rpe wrote:
         | Another way of saying this that I think is somewhat more
         | accurate is that they're constrained by designing for an
         | acceptable transistor budget, which sort of correlates to a
         | particular node. IIRC, Apple's chips are _significantly_ larger
         | in terms of transistor count than their competitor's chips. A
         | design that uses an equivalent # of transistors - a very messy
         | and inaccurate proxy for a requirement for perf parity - would
         | likely price it out of the range of most phone manufacturers
         | unless built on the newest process. Frankly, it may not be an
         | acceptable cost even at the newest node - Apple seems willing
         | to spend a bit more on their chips than most, and likely gets
         | better prices in any case due to the size of their orders.
        
           | pdpi wrote:
           | > A design that uses an equivalent # of transistors - a very
           | messy and inaccurate proxy for a requirement for perf parity
           | 
           | At some point it got twisted into "double the speed", but
           | Moore's Law as originally formulated was precisely about this
           | - doubling transistor count.
        
             | Symmetry wrote:
             | It wasn't really a matter of twisting. The phrase "Moore's
             | Law" got coined in an interview at the same 1975 conference
             | where Dennard presented on his scaling laws and has never
             | referred just to the first periodic doubling Moore noted in
             | his 1965 paper.
        
               | vlovich123 wrote:
               | Back then, the transistor switching speed was 1:1
               | correlated with size and the sizes we're talking about
               | then the size dominated (capacitance between gate &
               | source). That decoupled in the late 90s / early 00s (if
               | my recollection of news is correct) & kept getting more
               | decoupled. These days you can have a switching speed of
               | 604 Ghz but that doesn't translate to overall clock speed
               | (dominated by critical path latency of your pipeline) +
               | there's thermal issues.
               | 
               | Disclaimer: Not an EE / HW designer. Going off of memory
               | from tech news + some university courses (info may be
               | incorrect / stale).
        
               | Symmetry wrote:
               | It was more that leakage current (i.e. thermal issues)
               | and velocity saturation suddenly becoming constraints on
               | how much you could increase switching speed along with
               | the difficulty of high frequency clock distribution. Your
               | individual transistor switching speed is always going to
               | be a lot faster than your clock speed because a pipeline
               | stage has to be made up of many layers of transistors to
               | get anything useful done (including latch the signal at
               | the clock edge!) and each transistor will typically drive
               | multiple others.
               | 
               | I was seriously considering being a chip engineer for a
               | while and did my master's thesis on adder design.
        
           | tyingq wrote:
           | Another example might be this Cortex-X3 being the first in
           | ARM's X line to drop the 32 bit ISA, where Apple had dropped
           | that in the A11. That gave Apple several iterations to take
           | advantage of whatever simplifications or reclaimed transistor
           | budget came from dropping it.
           | 
           | 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.
        
             | kramerger wrote:
             | Hasn't aarch32 always been optional in armv8? I mean,
             | technically you can emulate it in software.
             | 
             | It was simply no market for solo aarch64 before, since a
             | lot of costumers wanted the backup of having aarch32
             | compatibility.
        
             | gsnedders wrote:
             | Cortex-X2 dropped A32 & T32.
        
               | tyingq wrote:
               | Ah...yep, I was was wrong there. Though still much later
               | than the Apple/A11...2017 vs 2021.
               | 
               | 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."_
        
         | mkj wrote:
         | Do Apple's chips keep 32bit compat? That seems a big win in the
         | x3.
        
           | msbarnett wrote:
           | No, like the X3 they dropped 32-bit compatibility (Apple
           | dropped it in the A11, ARM dropped it for Cortex-X in the X2)
        
         | gchadwick wrote:
         | > 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.
         | 
         | 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.
        
           | gumby wrote:
           | > I think there's also a tendency for everyone to want to do
           | their own CPU now.
           | 
           | 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.
        
             | rbanffy wrote:
             | > Apple spent billions for more than a decade on ARM
             | development before using their own design as a central
             | processor.
             | 
             | 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.
        
               | gumby wrote:
               | > For their computer platforms. Apple has been using ARM
               | since the Newton.
               | 
               | 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.
        
               | rbanffy wrote:
               | It took a long time for ARM to dominate the low-power
               | space (MIPS and POWER were contenders for a long time).
               | ARM started as a desktop processor and died on the
               | desktop before there was a space for low-power 32-bit
               | RISC devices.
               | 
               | 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.
        
               | dagmx wrote:
               | For Intel, they also missed a lot of targets in terms of
               | both delivery and thermals throughout the x86 Apple era.
               | 
               | As a company, they don't like being at the mercy of
               | someone else if they can help it.
        
               | rbanffy wrote:
               | > For Intel, they also missed a lot of targets in terms
               | of both delivery and thermals throughout the x86 Apple
               | era.
               | 
               | True. Up until now, it was always betting the company on
               | someone else's silicon roadmap. Now they control it
               | completely.
        
           | rsynnott wrote:
           | > I think there's also a tendency for everyone to want to do
           | their own CPU now.
           | 
           | 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.
        
             | gchadwick wrote:
             | > 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.
             | 
             | 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.
        
               | enragedcacti wrote:
               | I think there is a lot of room for competition in the
               | accelerator space e.g. GPUs, ML inference engines, video
               | encode/decode.
               | 
               | 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.
        
               | throw34 wrote:
               | This has been a popular topic for some time in the
               | computer architecture space.
               | 
               | " 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...
        
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