
Apple MacBook Pro lasts 135 minutes longer on battery in full screen mode - gbrown_
https://www.notebookcheck.net/Apple-MacBook-Pro-lasts-135-minutes-longer-on-battery-in-full-screen-mode.239966.0.html
======
personjerry
If you're a gamer who plays on sub-optimal hardware, chances are you already
know this. In general, full screen mode tends to perform better than windowed
mode. Windowed mode means that the OS has to render and handle logic for all
the window-y stuff, i.e. shadows, borders, close buttons, menus. In Windows 7
I recall a perf win was to turn off the Aero translucent window decorations,
and an even bigger perf win was to simply go full screen with your game.

~~~
hhmc
Not only that but you're guaranteeing yourself one or two extra frames of
input lag due to the double/triple buffering.

~~~
LeoNatan25
Double buffering is always enabled; there is no such thing as “single
buffering” in modern computer graphics.

What you are talking about is enforced v-sync to prevent tearing on the normal
desktop environment.

~~~
randyrand
Samsung Galaxy phones are single buffered when in VR mode. They 'race' the
beam by rendering to the left eye buffer while the right eye is being scanned
out. then switch.

Just a neat fact.

~~~
rsync
"They 'race' the beam by rendering to the left eye buffer while the right eye
is being scanned out."

Doesn't that mean they have _no_ framebuffer ?

My understanding of "racing the beam" is that it is only required when you
have no framebuffer at all - you are literally cramming the bits, in real
time, onto the display circuitry.

If you have even a single framebuffer, you write to that and _it_ handles
painting the actual pixels to the display circuitry.

~~~
randyrand
race the beam can have multiple usages. Its usage makes sense here IMO.

for the gearvr, the scan out circuitry operates independently and reads out
the bits from a buffer in memeory. There is still a buffer.

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al2o3cr
I wouldn't be surprised if there's a "fast path" for this in the hardware -
"decode H264 video to the entire screen" seems like a logical target for
optimization.

~~~
LeoNatan25
Hardware accelerated decoding is enabled even in windowed players. On Macs,
especially when using QuickTime, the only difference between fullscreen and
“windowed” windows is the size of the surface and the hidden Dock and menu
windows.

~~~
jgh
Full screen video could skip most of the other composition that needs to
happen, though. So while the video decoding itself may not be any different,
it certainly won't have to go through drawing everything else that would
otherwise be on the screen.

Edit: as the sibling noted too, they could also de-prioritize other apps since
presumably you're not really using them.

~~~
LeoNatan25
Yes, that is what I said in this thread in the first place; in fullscreen, the
window manager needs only draw the player window.

------
sillyclown666
"OS X v10.6 and later automatically optimize the performance of screen-sized
windows, allowing your application to take complete advantage of the window
server environment on OS X. For example, critical operating system dialogs may
be displayed over your content when necessary."

[https://developer.apple.com/library/content/documentation/Gr...](https://developer.apple.com/library/content/documentation/GraphicsImaging/Conceptual/OpenGL-
MacProgGuide/opengl_fullscreen/opengl_cgl.html#//apple_ref/doc/uid/TP40001987-CH210-SW4)

------
satysin
My guess would be that macOS shuts down all the additional composition
features when full screen is activated so no need for live previews (or even
rendering at all) of other windows, all those pretty bokeh effects, etc. Plus
it probably means they can switch to a more efficient hardware decoding
configuration as they can dump directly to the screen rather than into an
application window?

I am just guessing though. Interesting that the difference is over 2 hours
though, I wouldn't have guessed it would be that much.

------
abalone
Two best explanations:

1\. Screen brightness can be dimmed in full screen mode without a perceivable
difference.

2\. App nap. It's a macOS feature that dials down the power consumption of
apps when their windows aren't visible.

~~~
thanatropism
App nap is amazing.

Mac OS X reached an astounding level of technical goodness in Snow Leopard.
Downhill since then. When my Macbook died I bought a refurbished, shitty
Chromebook. Living off Azure Notebooks for any kind of computing...

~~~
PascLeRasc
App nap is really great, I agree. But you know you can still run Snow Leopard,
right? You could get an older pre-retina MBP for like $400 to run it at about
the same speed as a Chromebook will run ChromeOS.

~~~
ctrlrsf
Much less secure though.

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luigi23
I'm wondering whether this live blur effect might have played a big part here.
Since its full screen, macOS doesnt need to render all these fancy effects.
I'd like to see similar tests with live blur turned off.

~~~
LeoNatan25
Of course. If you disable it in settings, you should see a noticeable boost in
batter life (~1–1.5 hours in my testing).

~~~
ritchiea
Can you be more specific? What exactly do I need to disable to see a battery
life boost?

~~~
LeoNatan25
It's right there:
[https://news.ycombinator.com/item?id=14948178](https://news.ycombinator.com/item?id=14948178)

------
MBCook
That's pretty neat.

The thing that stands out to me like a sore thumb though is the 'load'
numbers. You only get 1 hour of battery life.

I know modern chips can be a hog but that terrible, especially compared to the
11 hours of light surfing on wifi.

This is the problem with optimizing power sipping all over the place. As soon
as you push things none of that matters and your battery time PLUMMETS.

I don't know what they could do though outside of doubling the battery
capacity.

~~~
toomuchtodo
Stop optimizing for pretty and add more battery. My laptop is a tool, not a
piece of art.

~~~
skybrian
There are FAA limits on how big a battery can be if you want to take it on a
plane. Your best bet is probably an external battery.

~~~
kalleboo
Apple used to stick 99 Wh batteries in the 15" Pros, but with the last 2
generations they downgraded that to 76Wh batteries (presumably since their
battery life targets are based on Safari browsing and QuickTime playback - or
at least that's all they advertise)

~~~
skybrian
Yes, I'd be curious to know why they don't push the limit anymore.

But in any case, we're talking a maximum of 30% improved battery life that you
can get by going bigger. Better efficiency when consuming power is likely to
make a larger difference.

------
LeoNatan25
It is not really surprising. All the window composition with frame-buffer
effects (such as multiple layers of blur) takes a toll.

Enabling “Reduce transparency” and “Reduce motion” in accessibility
preferences also causes a considerable battery gain on Macs.

~~~
ygra
As they note at the end, this only applies to OS X with QuickTime, but not to
Windows 10 on the same hardware.

So while it may be an obvious optimization to some people it doesn't seem to
be implemented everywhere it could be. Or the DWM is more efficient than OS
X's window composition stuff and there's no difference between windowed and
fullscreen modes. Either option probably will annoy some fanboys one way or
the other.

One thing that they may have done is to simply change the refresh rate of the
display to match the played video's (akin to GSync/Freesync) in fullscreen
mode. You can't do so in windowed mode since it will affect other
applications, but when a fullscreen video is shown you can safely do so and it
may save a bit of power.

~~~
mikewhy
> As they note at the end, this only applies to OS X with QuickTime, but not
> to Windows 10 on the same hardware.

> > Using the Windows Media Player in Bootcamp, power consumption was at a
> much higher 28.2 W, and we found absolutely no difference between regular
> and full screen playback.

Windows was less efficient overall, just with no difference in full-screen.

~~~
bwat49
They should have tested with the 'movies and tv' app that is now the default
video player in windows 10. From benchmarks I recall seeing, it's by far the
most battery efficient video player on the windows platform.

edit: [http://www.pcworld.com/article/3023430/hardware/tested-
vlc-v...](http://www.pcworld.com/article/3023430/hardware/tested-vlc-vs-
windows-10-video-player-the-winner-may-surprise-you.html)

~~~
dagaci
Windows media Player is actually deprecated on Windows 10 (2015) and you
actually have to make special efforts to use it.

Some info on UWP power usage:
[https://www.reddit.com/r/Windows10/comments/4iol5z/do_uwp_ap...](https://www.reddit.com/r/Windows10/comments/4iol5z/do_uwp_apps_use_less_battery/)

------
fixmycode
What I would've love to see is if this feature is unique to the QuickTime
player, and if it is, can it be ported to something like VLC.

------
_joel
Would this not be down to the GPU, if it's told to use full screen without
windowing, then it'll be more efficient?

~~~
jethro_tell
Yes, this isn't the only bloated window manager that gets more efficient when
it only has to draw one app without a window.

------
dwighttk
Do you see the same or similar results browsing in windowed vs fullscreen
modes?

(I rarely watch video on battery in a window, but I might start browsing
fullscreen on battery if there's a benefit)

------
jasonlotito
This is a feature that has been called out by Apple in the past with regard to
battery life. Even iPhones get better battery life when just doing video as
opposed to other things. In part, it's because of specialized hardware for
decoding. Even the headline here is misleading. It's not full screen mode.
It's explicitly using features Apple has made available for some time now.

That this is surprising is really interesting. I honestly thought this was a
known thing.

~~~
jclardy
The 2+ hour difference is comparing playing video windowed and fullscreen, not
video to other tasks.

~~~
jasonlotito
Yes, I know (and it's not just video fullscreen, it's video in QuickTime). And
as I said, I thought this was known. Apple has called this out. I mean, did
people really think that merely playing a video extended battery life? Or did
they just forget about those features that Apple talked about.

------
llcoolv
I am absolutely not surprised that almost all Apple users have failed to
notice the massive CPU usage of the window manager.

------
switchbak
This might sound like a plug, but I found it to be very useful/related: when
searching for a utility to control App Nap (suggested here) and actually have
more control over that, I found the App Tamer utility. This looks like I can
now throttle the CPU usage of background tasks like Chrome/Slack, etc.

I do a ton of road warrior stuff on my old MacBook, and I've been struggling
with a battery that craps out in under 2 hours due to all the background junk
in the Mac OS. This looks to be super useful to me, hopefully others will find
the same.

[https://www.stclairsoft.com/AppTamer/](https://www.stclairsoft.com/AppTamer/)

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azr79
this isn't news, app nap existed in macOS when it was still called OS X

------
chiefalchemist
I read a fair number of the comments. Most of the guesses/explanations on why
there's a difference make sense. But over 2 hours? That's a significant dip in
power consumption that doesn't seem to be explained by most of the comments.
Of course, I could be wrong. I'm not an internals junkie. (Sorry?)

------
djrogers
Should be noted that this testing appears to have been done _playing video_ in
full screen mode. macOS has a full screen mode that any app can take advantage
of, it would be good if someone could test that as well.

------
samat
Very click bait title. Sound like gain in any use case, where in reality it's
just video playback :((

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miga
That strongly suggests that Apple's window manager is suboptimal. Is it not?

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jordache
ok so they squeezed some more battery life for watching jackass the movie.

How about they figure out the combination that leads to consistent kernel
panic when plugging in/out external monitors.

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mattl
> Exciting: the MacBook Pro's video playback runs 135 minutes longer in full
> screen mode - the length of an entire feature film.

A feature film is anything longer than 40 minutes. This idea that movies need
to be 90 or 120+ minutes long is absurd.

~~~
abritinthebay
Dude, don’t be that guy. You know what they meant and everyone understood it.

~~~
mattl
I just made a film, it's a really common misunderstanding that films need to
be 90+ minutes long to be a feature film.

~~~
abritinthebay
Ok, right, I _know_. I’ve made films myself - shown them at festivals around
the world inc Cannes - and I’m aware. It’s true; you’re correct on the
definition.

The reason people are reacting negatively is not because of the truth value of
your point: it’s because your point was pedantic and _irrelevant_.

Is that time the length of _a_ feature film? Yes. Many of them. Does that mean
_all_ feature films have to be that long? No. Are _most_ feature films the
general public encounters ~90-120 mins? _Yes_.

So you’re not adding to the discussion. You’re being that “well, actually...”
guy.

I’m not trying to rag on you to be mean, I’m trying to help you understand why
it came across poorly.

~~~
mattl
I thought it was an interesting and relevant comment. I guess people disagree.
However, all the people replying telling me such just makes this place feel
hostile.

> I’m not trying to rag on you to be mean

Then downvote and move on, don't reply "Dude" :)

I'd be curious to see your work if you have an IMDb link though. If you're
going to reply with anything other than a link to your work, please don't.

~~~
abritinthebay
I prefer trying to be constructive to downvotes, YMMV.

The only thing that made it into IMDb was the animated short that got into
Cannes. I’m well out of that area now.

It’s called “Ignorance is Bliss”, if you’re interested.

~~~
mattl
I apologize for accusing you of downvotes. I'll check it out.

