Android 4.4 KitKat runtimes

There are lots of questions floating around regarding ART — the new experimental runtime that's included as a developer option in Android 4.4 KitKat. Anyone can enable it — just go to the developer settings. 

As described by Google:

ART is a new Android runtime being introduced experimentally in the 4.4 release. This is a preview of work in progress in KitKat that can be turned on in Settings > developer options. This is available for the purpose of obtaining early developer and partner feedback.

Will it make a difference to you as an end user? Maybe yes, maybe no — or maybe placebo? The short, short version? It's way early on this right now and most of us don't need to worry about it quite yet.

We talked some more about it on this week's podcast, and it's worth a five-minute breakout.


Reader comments

Five minutes on ART — the new Android runtime


What annoys me is some people are claiming that ART is allowing their Nexus 5 to get like 8 hrs of screen time.


It may help minimize background processes, etc, but that 1080p panel still sucks battery like no tomorrow. ART will help a bit, but it's not the second coming.

So you are telling people that they are wrong but it doesn't sound like you have a nexus 5 or kit kat. Maybe I am wrong but that's how it sounds. And if that's the case seriously just stop. Cause YOU DONT KNOW. who r you to tell people that have the phone and the new os and are actually using art that it doesn't work. I am skeptical to but let's keep the negativity down til you at least give it a try!

He has a point, though. People are always quick to judge something, before they've even tried it, if ever. This happens, every time a new device is released. People feel "left out," because their handset is now "old," lol.

For some people, ART may help, significantly even; for others, it may produce a mild, yet noticeable, performance bump; and for others it may have a placebo effect, or probably won't make a difference. But, a person that doesn't even have the phone has no room to judge, even if the claim seems a little preposterous.

I'm curious, to know where he read that battery life claim.

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I just read it on one website that it should increase battery life. But it has nothing to do w screen time.
I can assume that it has to increase by some percentage, because iPhone always outperformed android in idle states and web browsing. I'm not an expert but just comparing my experiences .

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Sure. I know, it probably won't equate to drastically better battery life, screen-on time, or performance. If it did, I'm sure ART would have been the default runtime, out of the box.

I can see it increasing "browsing time," for sure. Android 4.3 saw vast improvements to idle time. Browsing the Web, no matter what browser you use, is still one of the biggest battery drainers, though.

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I just read it on one website that it should increase battery life. But it has nothing to do w screen time.
I can assume that it has to increase by some percentage, because iPhone always outperformed android in idle states and web browsing. I'm not an expert but just comparing my experiences .

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I have an N5 and I have ART enabled and it does not add even an hour of battery life. It may add some but it hasn't drastically changed it.

^ I confirm what he says... Been running ART since yesterday day morning, still the same in battery performance.... I swear that Chrome browser runs better though.... Most likely a placebo effect.

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I've been running ART for a couple days also. Chrome is most definitely better. Scrolling is much improved. As a Matter of fact scrolling is much improved across the board. Its certainly no placebo effect.

Battery wise, I'm Noticing no real difference either. It's possible it could be slightly better, it's certainly not worse.

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Chrome isn't a native android app so I doubt it will have any effect. At best it would improve the menus but the web part will all be native.

Loved the nexus till I found out that on sprint I can not make a call and search the web at the same time.. $400+
Really did not want a Sammy phone but I have no I need my money back, OK google

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You can also browse during calls when connected to WiFi, too.

Posted via Android Central App, HTC One

All phones are like that on sprint. The network doesn't support both calling and data at the same time. You're issue isn't the N5... It's Sprint.

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I read that they have code which will make 1.x networks look like 3g in their nexus and some other smartphones they sell, unless you got better speeds before now on sprint then I'd blame the code

Posted via Android central app on my rooted LG Google Nexus 4

Lol, seems like people are lost on this issue. I always have lte and it don't work.Google said its sprint, sprint said it the nexus 5... Crazy

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Sorry, should of clarified EVO lte. Someone posted all Sprint phone were like that, just not true.

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Correct! the EVO 4G LTE supports Simultaneous Voice and Data on EVDO and LTE. Tri-Band LTE devices, (aka Sprint Spark), devices do not support SVLTE or SVDO. It comes down to cost to implement it, for the most part.

It really isn't that big of a deal breaker and once Sprint switches from 1X voice to Voice over LTE, we will have simultaneous Voice/Data once again.

I don't see developer option in I have to activate it?

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Received my N5 on Monday and changed to ART two days later. All my apps are working and seem to load more quickly. Battery life has improved. Not changing back to Dalvik.

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I been running it on my device 3 days now In my case battery life has increase significantly since switching I haven't measured it yet - but I have held off on unlocking and rooting ftm phone is running damn good on T-mobile the way I understand it ART will only work with Odexed apps going give a few more days but in definitely increase's battery life and transitions in and out of the applications

Lol, yeah. Unfortunately, he doesn't win the contest for longest run-on sentence. That honor, still, belongs to someone else, lol.

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Actually, I can speak some Spanish, as well.
My Spanish isn't as good as my English, but it'll get there.

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Let me help:

"I been running it on my device 3 days now. In my case battery life has increase significantly since switching. I haven't measured it yet - but I have held off on unlocking and rooting. Ftm phone is running damn good on T-mobile. The way I understand it ART will only work with Odexed apps. Going give a few more days but in definitely increase's battery life and transitions in and out of the applications."

Doesn't that read better? I learned that back in kinder.

I SWEAR! I activated ART 3 days ago, and since then my battery life has doubled,I now have 128GB of storage, my screen is 4k resolution and my speakers sound better than my $12,000 sound system in my home. And I don't care if any of you believe it cuz you don't have a Nexus 5 and don't know what you're talking about!

I can confirm that What'sApp force closes and doesn't work on ART.

I tried uninstalling it but then it won't let me install it back through Google Play. Gives me a run time error 24/package file invalid.
I deleted What's app folder from storage and from the data/data/ folder (via solid explorer) and rebooted and tried installing it again. Still no luck.

The moment I changed back to Dalvik it was fine and running again.

I'm sure it might be fixed in the future but just wanted to point it out for people who rely on What'sApp as their daily communication driver.

I do use hangouts for SMS and in general. But I have friends who aren't on Android and they are hardcore lovers of What'sApp. (I realize that Hangouts is cross platform).
There was a time when I used to convince them into doing stuff. I have lost all patience now.

On my phone the ART difference was dramatic. Apps open instantly now. Google Maps tiles populate far faster. It was not a trivial difference for me.

I've noticed only SLIGHTLY faster transitions. Except I can definitely second your observation about Maps. I can't believe how much faster the maps render with ART enabled.

Since I constantly use Maps, I'm keeping it and hoping for a quick WhatsApp fix (overseas bro).

I'm on the third day using ART and I have concluded that it doesn't improve battery life by any noticeable amount. At first I thought it did. I had been getting about 9 hours of use with 4 hours of screen time but when I turned on ART I got 15 with 4 hours of screen on. After reading other people's experiences without ART I think this is normal for the N5. Now what ART has improved is scrolling and app loads. Before, every once in a while I would notice stutter in the app transition animation, now that is almost entirely gone. I imagine this is because it no longer has to convert the byte code reducing app load processing.

Phil asked Jerry to explain what this feature was on the N5, I was hoping to get a real answer at this point but what we got was 5 minutes of Jerry telling us nothing. I still don't know exactly what this feature does to the OS. You would think that if Google put this feature on the phone someone could explain to the buyers of this phone just what this does and if we used it what we might expect. So far all we get is users of this phone writing in with their results and everyone is saying something different. Being a very long time Android owner and hacker I still have really no idea what this feature does. I hate that, I like to know everything about the phone I'm using, or at least the features that are available.

Shit, I just found out my 400$ nexus 5 can not search the web when I am on a phone call. Thinking of sending it back.

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If talking and surfing at the same time was something that was important to me, I would have looked into it before I spent $400(you know, personal responsibility and all) but sure, go ahead, blame the phone. Wouldn't want people to think that YOU could have screwed up.

Are you serious, what are you some Google ass lick or something. Shit all they should have done is make people aware of the pros and cons. Is that too much to ask or should that be expected.
If you can't make a statement that makes sense, then stop posting

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There is no way Google could possibly know every single question that everyone would have about the phone, so a pros and cons list couldn't ever help everyone. But I get your point. What Google should have done is have some sort of...lets call it "customer service" where people could ask questions about their devices.

Oh wait, they do. But asshats like you would rather just blame others for your own incompetence and act like its everyone else's fault because you were too stupid to ask a simple question when Google made people available for you to ask. I suggest you Google "personal responsibility" since you clearly have no idea what it means. It will serve you well in your life.

There's nothing to tell. It's an experimental build of the future runtime, put there so partners can experiment with it. It's tucked away in the developer settings, because it's not something users need to worry about right now. When it's complete, it will help prevent piracy, use more space for apps, and possibly be faster because of the way the code is interpreted by the VM.

Per a contact at Google, any major differences people are seeing are either placebo, or because the cache was rebuilt.


Jerry explained this very clearly. At this point this is something for developers. If you're not a developer then it's not for you, it will have no effect on your life, and there is no need for you to know anything about it. If you're not a developer then there's actually no reason for you to enable it. Hell, its part of the developer's options so if you're not a developer you shouldn't even be looking for or at it. If you are a developer, you should already know what you need to know about it. Not every feature of every phone is for every one.

Dalvik VM is a virtual machine that applications run on top of it. This allows developer applications to work on multitude of hardware without problems. Android runtime compiles the application into native code when it installs. It claims twice the performance since the application does not run in a virtual machine along with increased battery life. Downside is it takes longer to install applications.

This isn't a maybe this is good. Compiling apps into the native machine code is absolutely great, it's just better all around. I hope this becomes permanent in Android at some point.

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I will say I've had a noticeable improvement on battery life. I was thinking about returning my phone due to its horrendous battery life but ART has improved it substantially.

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The thing is battery life increases a fair degree on any and all Android devices for the first week or 2 so nobody can say what battery is truely like on N5 yet or if ART increases battery to any degree since the phone is only a week old as of now. I've had my N5 for a few days and am already getting 5hrs screen on time which is quite respectable, the only time it really Sucks battery is gaming so it's weird to put a Adreno 330 then a battery that doesn't allow you to take advantage of that top notch GPU for an extended period of time.

What I can say about turning on ART is that it definitely makes things more stable. When turned on I did not have a single app crash/force close, but when ART was not enabled I definitely had a few apps crash/force close.

I'll tell you guys straight up on my 32gb N5, I'm definitely noticing better battery life. Over the last two days, since have ART turned on, it's been lasting much longer. Much longer as in 3 to 4 hours longer doing the same tasks (Facebook, news, snapchat, forums, and emails). I consider myself a power user and the extra gains are noticeable on my end.

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