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Comment by clarry | Hacker News Reader

Ok, where is the benchmark that shows the performance parity? All I've ever seen is comparisons to low power mobile chips. And then extrapolation from there.

You can't just extrapolate and assume your 2W (or whatever) phone CPU will be like a 95W desktop if you just stick on a heatsink & fan and feed higher voltage & clocks to it.

If it were that simple, the CPU manufacturers could fire a whole lot of engineers.

It's like, you know, my Honda Accord is reaching performance parity with your Bugatti. (If I extrapolate based on how much I think I'd get performance by sticking in a big turbo and new exhaust, intercooler, and higher RPM redline. It's that simple, right?! No, actually it's not..)

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“In the space of one hundred and seventy six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over a mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oölitic Silurian Period, just a million years ago next November, the Lower Mississippi was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-pole. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo [Illinois] and New Orleans will have joined their streets together and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” -- Mark Twain

Intel and ARM are just approaching the same points from different directions, that's all.

We can equally say that you can't extrapolate and assume that your 45W x86, with lowered clock and voltage, will fit in the power budget of a mobile phone and still give good performance. But all these companies are throwing a lot of engineering effort at it and making solid progress. There's not some reason why x86, the architecture, should be faster than ARM. Intel has been enjoying a process advantage for many years now, and an enviable R&D budget, but that R&D budget is spent fighting against diminishing returns and in the meantime, competitors are catching up. As long as everyone can buy roughly the same node (a big "if", but looks like we're close enough), diminishing returns will bring everyone closer to parity.

But, benchmarks show this a bit better. Geekbench (I'm looking at Single Core):

https://browser.geekbench.com/mac-benchmarks

https://browser.geekbench.com/ios-benchmarks

iPad Pro 11-inch (iPad8,1) has the A12X at 2.5 GHz, score ~5000.

iMac 27-inch retina (iMac18,3) has the i7-7700K at 4.2 GHz, score ~5700.

This is not a cherry-picked comparison... this is just a comparison of whatever happens to be top of the line in both categories. Note that multi-core benchmarks will paint a slightly different picture, but that's very natural, since you can get a Mac with 18 core Xeons. Presumably, adding more cores to a mobile processor when you switch to desktop and can handle proportionally higher TDP, while not trivial, is not especially difficult either.

I assume that different benchmarks give different results as well. This is just one benchmark I know has results for both platforms.

You make a great point. I remember when I got my 12.9" iPad Pro (gen 2), and the graphics were fast as hell - Waaaaaay faster than my poor Mac Mini could do.

Based on that (and yes, both devices are now "old"), I'd trade my Mac Mini performance for the performance of my iPad without hesitation. Bring it, ARM !

I was going to post a text-heavy reply to you about that, but I decided not to. Essentially, my family got an iPad 4 and bluetooth keyboard case. A few years later, when Apple was prepping for their iPad Pro and positioning tablets as desktop replacements, I found that the work that I did was much easier on the iPad than it was on the Mac Mini (quad-core) that we had, including doing text editing and stuff of the sort.

Personally, if someone put an ARM laptop in front of me with a workable, non-spyware OS, I would take it in a heartbeat.

Just going to nitpick a bit here and point out that Apple has never used ARM's graphics. They started with imgtec and then Apple took over at some point, using largely the same architecture though.

Meanwhile your Mac Mini was using some form of Intel's integrated, which is notoriously trash tier. The very newest ones are OK sort of, but when push came to shove even Intel opted to ship AMD's Vega graphics in their own NUC instead.

Geekbench is, IIRC, a pretty non-representative benchmark. Nowhere is this more clear than looking at Samsung Exynos Geekbench results vs. their real-world performance. It's okay for comparing iterations on an architecture (e.g. A11 vs A12, SD845 vs SD855), but it falls apart a bit otherwise.

> Presumably, adding more cores to a mobile processor when you switch to desktop and can handle proportionally higher TDP, while not trivial, is not especially difficult either.

Multi-core scaling past a relatively low number is extremely difficult. AMD & Intel both have complex interconnect fabrics to handle this. You can see an example of this with Intel's shift from a ring bus to a router mesh design: https://www.anandtech.com/show/11550/the-intel-skylakex-revi...

Or AMD's new chiplet design with Epyc 2 of the IO die + core dies connected via InfinityFabric.

> iMac 27-inch retina (iMac18,3) has the i7-7700K at 4.2 GHz, score ~5700.

Be careful with those clock speeds because the Intel Core i7-8700B @ 3.2 GHz shows a nearly identical score.

And just below that supposedly the Intel Core i9-8950HK @ 2.9 GHz comes in just a bit lower at 5348

And the Intel Xeon W-2170B @ 2.5 GHz scored 5100. Higher than the A12X at the same clocks. That'd suggest Intel has an IPC advantage.

Of course the reality here is that the clock listed on that page are complete nonsense. It's not the clocks the CPU was running at while running the benchmark, which is a hugely important data point to have here given the variety in boost frequencies at different thermal/power situations. The i7-7700k wasn't running at 4.2ghz, it was probably running at 4.5ghz. And the i7-8700B wasn't running at 3.2ghz, it was probably running at 4.6ghz.

So depending on the actual clocks during the run the resulting scores may be more or less impressive. Similarly we don't know the actual power draw during those runs, which since we're talking about power efficiency here matters quite a bit.

https://homes.cs.washington.edu/~bornholt/post/z3-iphone.htm...

I wonder: how do they perform those computations? It is not (afaik) that there are compilers available for iOS. Or are there?

Honest question, just wondering.

Sorry: answered it myself. See the instructions:

https://github.com/jamesbornholt/z3-ios

You can't extrapolate too far, but you can reasonably extrapolate a 20% overclock of a chip that's running in low power mode.

OK, let's go with your analogy.

Five days a week you drive fifteen miles to work over roads constrained by traffic, getting up to 60MPH for two minutes and spending the rest of the trip at 0-30. On weekends you sometimes drive two hours to visit friends or go to a special event.

The fact is that the Honda is much more appropriate for your life than a Bugatti; 5 days a week you don't do anything that the Accord can't do, and on weekends you could take the money you saved by not buying the Bugatti and rent a Corvette or a Ferrari, and still come out ahead.

Most desktops and laptops spend 5 days a week being idle and waiting on RAM, SSDs, spinning disks, or network data... or worse, waiting for human input. During that time, you might as well have a cheap ARM. When you ask for peak power, mostly you could rely on an outboard GPU.

This is an argument for 'ARM chips are a viable CPU option in consumer laptops/desktops', but not for the title's original claim.

I think its a very interesting analogy actually, even if OT.

The Bugatti has higher performance but for 90% of people isn't the better car.

How long before Intel paint themselves into a corner by going for performance to justify their prices, when everyone just needs a bog standard ARM?

The title's original claim is reasonably supported in the article. I'm pointing out that even if ARM development mysteriously stops making gains against x86 development, it's entirely reasonable to think that Apple might announce that the next revision of OS X has an ARM version that runs on their new 16 hour Macbook Air and their new 14 hour Macbook.

I confess, I hadn't finished reading the original article when I posted my previous comment so I was operating under the assumption that ARM single-core performance was significantly further from parity than it apparently is. My original objection was that an external GPU can't shield you from lag and unresponsiveness in normal, everyday (ie. not designed to take advantage of GPU compute) software, but if the single core performance delta between an A12 and a reasonably recent desktop i7 is genuinely only 20% then that's not an issue.

My company does some embedded work. The problem with your analogy is that edge-cases drive CPU purchase decisions far more often than you would normally think.

A simple example: You have designed an ATM using a lower powered ARM CPU. 99.9% of the use-cases never tax the CPU beyond 30%. However, in specific cases where the ATM must simultaneously access the bill dispenser, printer, and note acceptor the hardware interrupts overwhelm the CPU and leads to 2-3 secs of "CPU lock". After those 3 secs, everything returns to normal.

The problem is that the bill dispenser protocol only allows for 1000ms in delay in ack to messages, thus when this situation occurs, the lag is longer than the protocol allows, so it errors out and FUBARs the entire transaction.

In this case, even though this only occurs .1% of the time, the existence of this edge-case will mandate that you not use this specific CPU.

Spoken another way: The ongoing issue of certain edge-cases will cost much more in the long term, than the extra $50 for a different CPU.

Having built exactly this kind of thing, a decent ARM CPU is more than capable of running these things together.

Network (TLS encryption), bill stacker over MDB (which requires continuous polling otherwise the devices shut down), credit card swipe/NFC, keyboard, display, receipt printer (USB) and dispenser.

Plenty of horse power left in both ARM Cortex-A8 and MIPS 24Kc configurations running Linux.

Great. But you seem to have missed that I was just providing an example.

However, to further the requirements. These days many people throw around the term "ATM" sort of indiscriminately. So, they call everything from a simple 3rd party cash dispensing kiosk to full-on bank automation centers "ATM's".

The problem is, that for a simple cask dispensing kiosk, you may be totally correct. Linux + ARM may work fine. However, the more functionality this device is suppose to have (ie. do 90% of the functions of a real bank teller: deposit checks, cash checks, etc), then the more these edge-cases become an issue.

Because of this tight integration with backend banking system, and regulatory requirements, these edge cases will become magnified (i.e. who says you can use linux?). Additionally, since all other players in this market also have to deal with all these issues, the $50 difference in CPU cost is totally absorbed into the rather high-dollar price tag associated with this automated teller.

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