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

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

#91

Post by rahkiin »

jopsen wrote: post #73
FlyingAvatar wrote: post #52

Earlier quoted context omitted.

It's pretty difficult to imagine. 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 u…

Isn't it also easier to license ARM, because that's the whole point of the ARM Corporation. It's not like Intel or AMD are known for letting other customize their existing chip designs.

Apple was a very early investor in ARM and is one of the few with a perpetual license of ARM tech

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

#92

Post by guerrilla »

somanyphotons wrote: post #90
exmadscientist wrote: post #2

This is an entirely uncontroversial take among experts in the space. x86 is an old CISC-y hot mess. RISC-V is a new-school hyper-academic hot mess. Recent ARM is actually pretty good. And none of it matters, because the uncore and the fabrication details (in particular, whether things have been tuned to run full speed demon or full power sipper) completely dominate the ISA. In the past x86 didn't dominate in low powe…

I'd love to see what would happen if AMD put out a chip with the instruction decoders swapped out for risc-v instruction decoders

Indeed. We don't need it, but I want it for perfectionist aesthetic completion.

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

#93

Post by Yizahi »

fluoridation wrote: post #69
toast0 wrote: post #67

Earlier quoted context omitted.

I think the fundamental difference between an Apple CPU and an Intel/AMD CPU is Apple does not play in the megahertz war. The Apple M1 chip, launched in 2020 clocks at 3.2GHz; Intel and AMD can't sell a flagship mobile processor that clocks that low. Zen+ mobile Ryzen 7s released Jan 2019 have a boost clock of 4 GHz (ex: 3750H, 3700U); mobile Zen2 from Mar 2020 clock even higher (ex: 4900H at 4.4, 4800H at 4.2). Inte…

Does anyone actually care at all about frequencies? I care if my task finishes quickly. If it can finish quickly at a low frequency, fine. If the clock runs fast but the task doesn't, how is that a benefit? 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 y…

It's only recently when consumer software has become truly multithreaded. Historically there were major issues with that until very recently. Remember Bulldozer fiasco? They bet on the parallel execution more than Intel at the same time, e.g. same price Intel chip was 4 core, while AMD had 8 cores (consumer market). Single thread performance had been the deciding factor for decades. Even today AMDs outlier SKUs with a lot of cores and slightly lower frequencies (like 500 MHz lower or so) are not a topic of the day in any media or forum community. People talk about either top of the line SKU or something with low core count but clocking high enough to be reasonable for lighter use. Releasing low frequency high core count part for consumers would be greeted with questions, like "what for is this CPU?".

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

#94

Post by peterfirefly »

Findecanor wrote: post #22
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)?

You mean Atom tablets running Android ? I have a ten-year old Lenovo Yoga Tab 2 8" Windows tablet, which I still use at least once every week. It is still useful. Who can say that they are still using a ten-year old Android tablet?

My iPad Mini 4 turns 10 in a month.

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

#95

Post by wvenable »

whynotminot wrote: post #33
exmadscientist wrote: post #2

This is an entirely uncontroversial take among experts in the space. x86 is an old CISC-y hot mess. RISC-V is a new-school hyper-academic hot mess. Recent ARM is actually pretty good. And none of it matters, because the uncore and the fabrication details (in particular, whether things have been tuned to run full speed demon or full power sipper) completely dominate the ISA. In the past x86 didn't dominate in low powe…

An annoying thing people have done since Apple Silicon is claim that its advantages were due to Arm. No, not really. The advantage is Apple prioritizing efficiency, something Intel never cared enough about.

By prioritizing efficiency, Apple also prioritizes integration. The PC ecosystem prefers less integration (separate RAM, GPU, OS, etc) even at the cost of efficiency.

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

#96

Post by Jensson »

gigatexal wrote: post #85
tracker1 wrote: post #65

Earlier quoted context omitted.

And 20% or so of that difference is purely the fab node difference, not anything to do with the chip design itself. Strix Halo is a much better comparison, though Apple's M4 models do very well against it often besting it at the most expensive end. On the flip side, if you look at servers... Compare a 128+core AMD server CPU vs a large core ARM option and AMD perf/watt is much better.

Wait are you saying the diff in perf per watt from apple arm to x86 is purely on fab leading edge ness?

Basically yeah, if you compare CPU from same fab then its basically the same.

Its just Apple buys next gen fabs while AMD and intel has to be on last gen, so the M computers people compare are always one fab gen ahead. It has very little to do with CPU architecture.

They do have some cool stuff about their CPU, but the thing most laud them for has to do with fabs.

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

#97

Post by nly »

rahkiin wrote: post #91
jopsen wrote: post #73

Earlier quoted context omitted.

Isn't it also easier to license ARM, because that's the whole point of the ARM Corporation. It's not like Intel or AMD are known for letting other customize their existing chip designs.

Apple was a very early investor in ARM and is one of the few with a perpetual license of ARM tech

And an architect license that lets them modify the ISA I believe

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

#98

Post by vt240 »

peterfirefly wrote: post #94
Findecanor wrote: post #22

Earlier quoted context omitted.

You mean Atom tablets running Android ? I have a ten-year old Lenovo Yoga Tab 2 8" Windows tablet, which I still use at least once every week. It is still useful. Who can say that they are still using a ten-year old Android tablet?

My iPad Mini 4 turns 10 in a month.

Yeah, I got to say in our sound company inventory I still use a dozen 6-10 year old iPads with all the mixers. They run the apps at 30fps and still hold a charge all day.

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

#99

Post by rasz »

yndoendo wrote: post #38
wlesieutre wrote: post #15

Earlier quoted context omitted.

VIA used to make low power x86 processors

Fun fact. The idea of strong national security is the reason why there are three companies with access to the x86 ISA. DoD originally required all products to be sourced by at least three companies to prevent supply chain issues. This required Intel to allow AMD and VIA to produce products based on ISA. For me this is good indicator if someone that talks about good national security knows what they are talking about…

Intel didnt "allow" VIA anything :). Via acquired x86 tech from IDT (WinChip Centaur garbage) in a fire sale. IDT didnt ask anyone about any licenses, neither did Cyrix, NextGen, Transmeta, Rise nor NEC.

Afaik DoD wasnt the reason behind original AMD second source license, it was IBM forcing Intel on chips that went into first PC.

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

#100

Post by fluoridation »

Yizahi wrote: post #93
fluoridation wrote: post #69

Earlier quoted context omitted.

Does anyone actually care at all about frequencies? I care if my task finishes quickly. If it can finish quickly at a low frequency, fine. If the clock runs fast but the task doesn't, how is that a benefit? 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 y…

It's only recently when consumer software has become truly multithreaded. Historically there were major issues with that until very recently. Remember Bulldozer fiasco? They bet on the parallel execution more than Intel at the same time, e.g. same price Intel chip was 4 core, while AMD had 8 cores (consumer market). Single thread performance had been the deciding factor for decades. Even today AMDs outlier SKUs with…

Are we just going to pretend that frequency = single-thread performance? I'm fine with making that replacement mentally, I just want to confirm we're all on the same page here.

>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.

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