Comment by computator | Hacker News Reader

Comment by computator | Hacker News Reader

> I have a big fat i7 CPU that I do most of my work on, and a brand new Pixel XL: the fastest phone in the world. What do you think the phone performance will be? It’s only 10%. If I slow my i7 down by ten times, it is the same speed as the $1,400 phone in front of me.

That's the most surprising thing I learned from the article. But I'm still a little skeptical about this. One well-known CPU comparison site[0] gives the following scores:

- The fastest desktop system they rated[1], which happens to have an i7 CPU just as the author is using, is rated 9206.

- Google Pixel XL smartphone[2] gets a score of 8153.

In other words, the Pixel comes out as having 89% of the performance of the fastest desktop system.

I looked at some other metrics for comparing systems, and I'm not seeing how smartphones are only 10% as fast as desktops -- neither in average cases nor in extreme cases (fastest desktop vs fastest smartphone).

[0] PassMark Software Pty Ltd. Their PassMark rating is a composite of tests for CPU, disk, 2D & 3D graphics, and memory.

[1] http://www.passmark.com/baselines/top.html

[2] http://www.androidbenchmark.net/phone.php?phone=Google+Pixel...

Take a look at this talk on why mobile devices are so much slower than desktop devices ( they are indeed 10x slower in the traces I have looked at too) - https://youtu.be/4bZvq3nodf4

Also look at the speedometer benchmark (http://browserbench.org/Speedometer/) for a more realistic comparison of how slow your mobile device is compared to your desktop when running real world apps. Here are some numbers from the benchmark from some devices - http://benediktmeurer.de/2016/12/16/the-truth-about-traditio...

> the Pixel comes out as having 89% of the performance of the fastest desktop system.

Do you really think we're expending 20-30 times the power for a 12 % compute speed-up?

Just to clarify, the two numbers you quote are different benchmarks. You can't compare them, lest say "oh, they're only different by 10 percent".

I agree that the 20-30x greater power consumption is hard to reconcile with the benchmarks I quoted. So, yes, something doesn't make sense; the benchmark is not taking into account something or I don't know what.

> the two numbers you quote are different benchmarks

But I don't agree with explanation. Both benchmarks are "PassMarks" (a proprietary measure devised by that company). I don't see them saying that their PassMarks for desktops are different than their PassMarks for smartphones.

That metric is likely multi-core performance. Contrarily, since JS is single-threaded (usually), the very weak single cores in a mobile processor don't do as well.

The bottom line is the power consumption. A big fat i7 (desktop) can draw 91W, while a fanless, battery operated smartphone can pull from 5 to 10W.

Power optimization come at a performance cost.

Android phones still compare well on CPU metrics but poorly on browser/JS metrics.

If a beefy desktop is 100 I'd guess the real world (todomvc) benchmarks are 100/90/20 for desktop/android/iOS, for a recent android and an iPhone 7.

So CPU power (sadly) doesn't translate directly to browser performance as well on android as it does on iOS.

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