ART has better performance and better battery life on paper at least. Should I consider switching to it on my moto g? What are the results I can expect? What precautions should I take? Is it easy to turn back to dalvik?

closed as primarily opinion-based by Chahk, bmdixon, ale, onik Jun 27 '14 at 9:05

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • It's about the same. Optimised Dalvik and ART are pretty much identical except some apps don't have ART support yet. Any differences I saw were completely placebo. Why not just try it sure and see... This is probably off topic as being opinion based. – RossC Jun 26 '14 at 13:02
  • @RossC What device you have? – kBisla Jun 26 '14 at 21:28
  • S4 Google Edition, Nexus 4, 5 and 7 (2012 one) in terms of ART compatible devices. And a GTi9505 Galaxy S4 I sometimes run AOSP ROMs on. – RossC Jun 27 '14 at 7:35

Just try it by yourself. I've felt no real difference. Maybe it is something that is device specific or there is just a very small difference.

But it can change with Android 5.0 'L' because ART on Android 4.4 is some sort of beta version.

Switching to ART is as easy as switching back to Dalvik.

Settings > Developer Options > Select Runtime.

There you can choose ART.

You have to reboot your phone to apply the changes.

If you want to go back to Dalvik, redo the steps and select Dalvik.

  • It's worth noting that currently not all apps support ART, seeing how it's still in beta. – Chahk Jun 26 '14 at 14:48
  • 2
    @Chahk As it's ART that's still in beta, it would be fairer to say that it doesn't support all apps. – Dan Hulme Jun 26 '14 at 17:20
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    BTW how many apps we're talking about here? 1%? – kBisla Jun 26 '14 at 21:27

It's worth noting that rebooting after switching runtimes may take several hours - at least this has been my experience. This is because the ART recompiles all your applications. It may even do it more than once if the process is interupted (e.g. due to battery drain) - i.e it start over again at the top.

I'm hoping that switching back will be quicker since hopefully the compile step (unecessary for the Dalvik JIT) is what has slowed it down. I have not yet switched a device back to Dalvik so I'm not sure if this is correct or not.

  • Thanks for the heads up! Did you notice by how much your apps expanded in size after switching? Also, what about performance and battery life? – kBisla Jun 26 '14 at 21:25
  • I did not see a noticeable size difference - mind you for the most part I am using things like Gmail, Youtube, and Chrome so they may be better suited for ART. – G. Cito Jun 27 '14 at 0:49

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