Apple did a ton of work on the power efficiency of iOS on their own ARM chips for iPhone for a decade before introducing the M1.
Since iOS and macOS share the same code base (even when they were on different architectures) it makes much more sense to simplify to a single chip architecture that they already had major expertise with and total control over.
There would be little to no upside for cutting Intel in on it.
It's not like Intel or AMD are known for letting other customize their existing chip designs.
Genuinely asking -- what is it due to? Because like the person you're replying to, the m* processors are simply better: desktop-class perf on battery that hangs with chips with 250 watt TDP. I have to assume that amd and intel would like similar chips, so why don't they have them if not due to the instruction set? And AMD is using TSMC, so that can't be the difference.
If you don't care to clock that high, you can reduce space and power requirements at all clocks; AMD does that for the Zen4c and Zen5c cores, but they don't (currently) ship an all compact core mobile processor. Apple can sell a premium branded CPU where there's no option to burn a lot of power to get a little faster; but AMD and Intel just can't, people may say they want efficiency, but having higher clocks is what makes an x86 processor premium.
In addition to the basic efficiency improvements you get by having a clock limit, Apple also utilizes wider execution; they can run more things in parallel, this is enabled to some degree by the lower clock rates, but also by the commitment to higher memory bandwidth via on package memory; being able to count on higher bandwidth means you can expect to have more operations that are waiting on execution rather than waiting on memory, so wider execution has more benefits. IIRC, Intel released some chips with on package memory, but they can't easily just drop in a couple more integer units onto an existing core.
The weaker memory model of ARM does help as well. The M series chips have a much wider out of order window, because they don't need to spend as much effort on ordering constraints (except when running in the x86 support mode); this also helps justify wider execution, because they can keep those units busy.
I think these three things are listed in order of impact, but I'm just an armchair computer architecture philosopher.
My understanding is that both Intel and AMD are pushing high clocks not because it's what consumers want, but because it's the only lever they have to pull to get more gains. If this year's CPU is 2% faster than your current CPU, why would you buy it? So after they have their design they cover the rest of the target performance gain by cranking the clock, and that's how you get 200 W desktop CPUs.
>the commitment to higher memory bandwidth via on package memory; being able to count on higher bandwidth means you can expect to have more operations that are waiting on execution rather than waiting on memory, so wider execution has more benefits.
I believe you could make a PC (compatible) with unified memory and a 256-bit memory bus, but then you'd have to make the whole thing. Soldered motherboard, CPU/GPU, and RAM. I think at the time the M1 came out there weren't any companies making hardware like that. Maybe now that x86 handhelds are starting to come out, we may see laptops like that.
>Releasing low frequency high core count part for consumers would be greeted with questions, like "what for is this CPU?".
It's for homelab and SOHO servers. It won't get the same attention as the sexy parts... because it's not a sexy part. It's something put in a box and stuff in a corner to chug away for ten years without looking at it again.
That's not really what we're talking about. Apple's cores are faster yet lower clocked. (Not just faster per clock but absolutely faster.) So some people are wondering if Intel/AMD targeting 6 GHz actually reduced performance.
But most every OS can.
(This is mostly because resolving priority inversions turns out to be very important on a phone, and almost noone designs for this properly because it's not important on servers.)
I think this is very context dependent. Is this a big, heavy 15”+ desktop replacement notebook where battery life was never going to be a selling point in the first place? One of those with a power brick that could be used as a dumbbell? Sure, push those clocks.
In a machine that’s more balanced or focused on portability however, high clock speeds do nothing but increase the likelihood of my laptop sounding like a jet and chewing through battery. In that situation higher clocks makes a laptop feel less premium because it’s worse at its core use case for practically no gain in exchange.
They historically haven't. They've wanted the higher single-core performance and frequency and they've pulled out all the stops to get it. Everything had been optimized for this. (Also, they underinvested in their uncores, the nastiest part of a modern processor. Part of the reason AMD is beating Intel right now despite being overall very similar is their more recent and more reliable uncore design.)
They are now realizing that this was, perhaps, a mistake.
AMD is only now in a position to afford to invest otherwise (they chose quite well among the options actually available to them, in my opinion), but Intel has no such excuse.
Thank you.
I suspect one of the issues is that pushing the clock is a really easy way to get an extra 2% so you can claim the crown of fastest or try to win benchmarks. It’s easy to fall into a trap of continuing to do that over and over.
But we know the long-term result. You end up blasting out a ton of heat and taking up a ton of power, even though you may only be 10% faster than a competitor who did things differently. Or worse you try to optimize for ever increasing clocks and get stuck like the Pentium 4.
As said up thread, no one really compares Apple CPU speeds with megahertz. That’s partially because Apple doesn’t talk about it or emphasize it which makes it more difficult, and partially because it’s not like you have a choice anyway.
It would never happen but it would be interesting to see how things would develop if it was possible to simply ban talking about clock speeds somehow. What would that do to the market?
And that has made all the difference.
- more advanced silicon architecture. Apple spends billions to get access to the latest generation a couple of years before AMD.
- world class team, with ~25 years of experience building high speed low power chips. (Apple bought PA Semi to make these chips, which was originally the team that build the DEC StrongARM). And then paid & treated them properly, unlike Intel & AMD
- a die budget to spend transistors for performance: the M chips are generally quite large compared to the competition
- ARM's weak memory model also helps, but it's very minor IMO compared to the above 3.
- a die budget to spend transistors for performance: the M chips are generally quite large compared to the competition
re: apple getting exclusive access to the best fab stuff: https://appleinsider.com/articles/23/08/07/apple-has-sweethe... . Interesting.
I think Apple helps them with money (loan?) to get some of the equipment or build the new lines. In exchange they get first shot at buying capacity.
And of course Apple is certainly paying for the privilege of the best process. At least more than other companies are willing. And they must buy a pretty tremendous volume across a couple of sizes.
It benefits both companies, otherwise they wouldn’t do it.
Relatively properly. Nothing like the pampering software people get. I've heard Mr. Srouji is very strict about approving promotions personally etc.
(…by heard I mean I read Blind posts)
P.S. hearsay and speculation, not direct experience. I haven't worked at Apple and anybody who has is pretty closed lip. You have to read between the lines.
P.P.S. It's sort of a circular argument. I say Apple has the best team because they have the best chip && they have the best chip because they have the best team.
But having worked (briefly) in the field, I'm very confident that their success is much more likely due to having the best team rather than anything else.
Apple's primary product is consumer smartphones and tablets so they are solely focused on power efficient mobile chips.
Mostly memory/cache subsystem.
Apple was willing to spend a lot of transistors on cache because they were optimizing the chips purely for mobile and can bury the extra cost in their expensive end products.
You will note that after the initial wins from putting stonking amounts of cache and memory bandwidth in place, Apple has not had any significant performance jump beyond the technology node improvements.
There's tons of people that would pay $300+ for an equivalent perf + heat x86 competitor.
The M2 was certainly nothing amazing in jump.