Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

AMD claims Arm ISA doesn't offer efficiency advantage over x86

techpowerup.com

Post reply on HN
Print view View original

351–360 of 446 posts

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#351

Post by boxed »

ohdeargodno wrote: post #318
boxed wrote: post #309

Earlier quoted context omitted.

He said "per watt", that's still true. You just talked about max throughput, which no one is discussing.

It's not, because Apple purposefully lied on their marketing material. Letting a 3090 go on full blast brings it pretty much in line in perf/watt. Your 3090 will not massively thermal throttle after 30 minutes either, but the M1 Ultra will. So, yes, if you want to look good on pointless benchmarks, a M1 ultra ran for 1 minute is more efficient than a downclocked 3090.

https://techjourneyman.com/blog/m1-ultra-vs-nvidia-rtx-3090/

Look at that updated graph which has less BS. It's never close in perf/watt.

The BS part about apples graph was that they cut the graph short for the nvidia card (and bending the graph a bit at the end). The full graph still shows apple being way better per watt.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#352

Post by ashirviskas »

sgc wrote: post #340
petrichorko wrote: post #329

Earlier quoted context omitted.

To me it's not as simple as comparing the efficiency under full load. I imagine the efficiency on x86 as some kind of log curve, which translates to higher power consumption even on lighter loads. Apple's ARM implementation tends to eat a lot less power on tasks that happen most of the time, hence greatly improving the battery life. I've tried a Ryzen 7 that had a similar efficiency to an M1 according to some tests,…

The OS matters, and I would guess you were using two different OSes? I have no doubt macOS running on an m1 is more optimized than whatever you were using on the ryzen. I recently had to remove Windows completely from a few years old laptop with an 12th gen cpu and a Intel Iris / GeForce RTX 3060 Mobile combo because it was running very hot (90c+) and the fans were constantly running. Running Linux, I have no issues.…

OS does matter, with Linux my M1 macbook gets kinda hot and it cannot do more than 1.5-2h of google meetings with cameras on. IIRC google meetings on macos were at least a bit more efficient.

Though it has definitely been getting better in the last 1.5 years using Asahi Linux and in some areas it is a better experience than most laptops running Linux (sound, cameras, etc.). The developers even wrote a full fledged physical speaker simulator just so it could be efficiently driven over its "naive" limits.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#353

Post by mrsmrtss »

tester756 wrote: post #140
rafaelmn wrote: post #136

Earlier quoted context omitted.

C# syntax is faster than Java because Java has no way to define custom value types/structs (last time I checked, I know there was some experimental work on this)

and yet there's more Java in HFT than C# And don't get me wrong, I'm C# fanboi that'd never touch Java, but JVM itself is impressive as hell, so even despite not having (yet) value types/structs, Java is still very strong due to JVM (the implementation). Valhalla should push it even further.

It may also be related to the fact that .NET until now does not have any GC with super low latency pauses, but there are interesting development going on recently regarding this - https://github.com/dotnet/runtime/discussions/115627.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#354

Post by simonh »

ben-schaaf wrote: post #349
devnullbrain wrote: post #347

Earlier quoted context omitted.

I want to measure the device how I use it. Race-to-sleep and power states are integral to CPU design.

Yes they are, but only one of those is at all affected by the choice of ISA. If modern AMD chips are better at race-to-sleep than an Apple M1 and still get worse battery life then the problem is clearly not x86-64.

Right, so as I understand it people see that x86-64 designs score poorly on a set of benchmarks and infer that it is because they are x86-64.

In fact it’s because that manufacturer has made architectural choices that are not inherent to the x86-64 ISA.

And that’s just hardware. MacOS gets roughly 30% better battery life on M series hardware than Asahi Linux. I’m not blaming the Asahi team, they do amazing work, they don’t even work on many of the Linux features relevant to power management, and Apple has had years of head start on preparing for and optimising for the M architecture. It’s just that software matters, a lot.

So if I’m reading this right, ISA can make a difference, but it’s incremental compared to the many architectural decisions and trade offs that go into a particular design.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#355

Post by txrx0000 »

aurareturn wrote: post #336
txrx0000 wrote: post #332

Earlier quoted context omitted.

Pardon my loose choice of words regarding the Mac-like efficiency. I was referring to the fact that the battery life is comparable to the M3 in day-to-day use, as demonstrated at around the 5:00 mark in the third video I linked. In the same video, they also measure perf/watt under heavy load, and it's close to the M1, but not the latest gen M4. I think that's pretty good considering it's a first gen product. Regardin…

In the same video, they also measure perf/watt under heavy load, and it's close to the M1, but not the latest gen M4. I think that's pretty good considering it's a first gen product. Which video and timestamp? Are you aware that LNL throttles heavily when on battery life? On battery life, M1 is a whopping 1.5x faster in single thread.[0] That makes M4 2.47x faster when compared to LNL on battery. So no, LNL is very f…

I suspect the throttling behavior has to more do with the power settings used during testing or OEM tuning on specific models.

https://www.youtube.com/watch?v=ymoiWv9BF7Q

In this video, they show the perf/watt curves at 8:30. And they show the on-battery vs on-wall performance at 18:35 across a wide variety of benchmarks, not just Geekbench. They used a Lenovo YOGA Air 15 on Window 11's "Balanced" power plan for their tests. The narrator specifically noted the Macbook-like on-battery performance.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#356

Post by aurareturn »

txrx0000 wrote: post #355
aurareturn wrote: post #336

Earlier quoted context omitted.

In the same video, they also measure perf/watt under heavy load, and it's close to the M1, but not the latest gen M4. I think that's pretty good considering it's a first gen product. Which video and timestamp? Are you aware that LNL throttles heavily when on battery life? On battery life, M1 is a whopping 1.5x faster in single thread.[0] That makes M4 2.47x faster when compared to LNL on battery. So no, LNL is very f…

I suspect the throttling behavior has to more do with the power settings used during testing or OEM tuning on specific models. https://www.youtube.com/watch?v=ymoiWv9BF7Q In this video, they show the perf/watt curves at 8:30. And they show the on-battery vs on-wall performance at 18:35 across a wide variety of benchmarks, not just Geekbench. They used a Lenovo YOGA Air 15 on Window 11's "Balanced" power plan for thei…

Reviewers always use max performance setting for benchmarks and then max battery life for battery tests. That's how people get tricked. When they actually buy the laptop and use it for themselves, they complain that it's slow when on battery life or hot/loud when plugged in.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#357

Post by Voultapher »

wmf wrote: post #27
mananaysiempre wrote: post #8

Earlier quoted context omitted.

> x86 didn't dominate in low power because Intel had the resources to care but never did Remember Atom tablets (and how they sucked)?

That's the point. Early Atom wasn't designed with care but the newer E-cores are quite efficient because they put more effort in.

The PMICs were also bad, plus the whole Windows software stack - to this day - is nowhere nearly as well optimized for low background and sleep power usage as MacOS and iOS are.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#358

Post by BirAdam »

slimginz wrote: post #5

IIRC There was a Jim Keller interview a few years ago where he said basically the same thing (I think it was from right around when he joined Tenstorrent?). The ISA itself doesn't matter, it's just instructions. The way the chip interprets those instructions is what makes the difference. ARM was designed from the beginning for low powered devices whereas x86 wasn't. If x86 is gonna compete with ARM (and RISC-V) then…

Jim Keller did say essentially that, and I think this is proven in two different facts.

First, x86 hasn't directly executed x86 instructions in a very long time.

Second, Rosetta 2.

ISA doesn't matter. Logic matters. Cache matters. Branch prediction and speculative execution matter. Buffers matter. Instruction reordering matters. Node size and packaging matter. SIMD matters for some workloads. Etc.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#359

Post by thechao »

KingOfCoders wrote: post #268
michaelmrose wrote: post #260

Earlier quoted context omitted.

RTX3090 is a desktop part optimized for maximum performance with a high-end desktop power supply. It isn't meaningful to compare its performance per watt with a laptop part. Saying it offers a certain wattage worth of the desktop part means even less because it measures essentially nothing. You would probably want to compare it to a mobile 3050 or 4050 although this still risks being a description of the different no…

It's no comparison at all, the person who bought a 3090 in the 30xx days wanted max gaming performance, someone with an Apple laptop wants longer battery usage. It's like comparing an F150 with an Ferrari, a decision that no buyer needs to make.

> It's like comparing an F150 with a Ferrari, a decision that no buyer needs to make.

... maybe a Prius? Bruh.

Re: AMD claims Arm ISA doesn't offer efficiency advantage over x86

#360

Post by steveBK123 »

exmadscientist wrote: post #247
jorvi wrote: post #224

Earlier quoted context omitted.

Nice followup to your link: https://chipsandcheese.com/p/arm-or-x86-isa-doesnt-matter . Personally I do not entirely buy it. Intel and AMD have had plenty of years to catch up to Apple's M-architecture and they still aren't able to touch it in efficiency. The PC Snapdragon chips AFAIK also offer better performance-per-watt than AMD or Intel, with laptops offering them often having 10-30% longer battery life at simila…

Yes, Intel/AMD cannot match Apple in efficiency. But Apple cannot beat Intel/AMD in single-thread performance. (Apple marketing works very hard to convince people otherwise, but don't fall for it.) Apple gets very, very close, but they just don't get there. (As well, you might say they get close enough for practical matters; that might be true, but it's not the question here.) That gap, however small it might be for…

> looks less and less like the right choice with every passing month

It does seem like for at least the last 3-5 years it's been pretty clear that Intel x86 was optimizing for the wrong target / a shrinking market.

HPC increasingly doesn't care about single core/thread performance and is increasingly GPU centric.

Anything that cares about efficiency/heat (basically all consumer now - mobile, tablet, laptop, even small desktop) has gone ARM/RISC.

Datacenter market is increasingly run by hyperscalers doing their own chip designs or using AMD for cost reasons.

Post reply on HN