Is it worth using Android Runtime (ART) on Google’s Nexus 5?

Google’s new Android Runtime (ART) is available to use on the Nexus 5 as a part of Android 4.4, but is it really worth turning on and using? After spending the last couple of days with the heir apparent to Dalvik for Android, it’s safe to say that while there are no Earth shattering changes to the overall experience, it certainly doesn’t hurt to make the switch.

ART is very simple to enable, as long as you’ve got a few minutes (and about 8 per cent of your total battery to spare if you’re not connected to an outlet). You’ll need to enable the developer settings first. Head to About Phone in your Settings and violently bash the Build Number with your finger until the OS tells you that you’re a developer. When you press the back button, there will be a new section for Developer options. Inside that menu you’ll find runtime options, where you can select ART and reboot your phone.

Once the fun has started, here’s what you can expect…

Your new Nexus 5 is going to feel just a touch snappier when you first boot with ART. This isn’t ART being awesome, this is your phone operating with a completely empty cache. The truth is that the Snapdragon 800 processor in the Nexus 5 is already screaming fast, so it’s not like it really needs to be any faster for navigating the OS or launching apps. The most impressive thing here is that there really isn’t any noticeable difference. Despite being not quite ready for primetime – which is why it isn’t the default – ART is already just as capable as Dalvik.

After three whole days of use, making sure every app I would normally use was run and played with, there wasn’t a single experience that felt any different. I didn’t expect there to be any real issues because everything’s being compiled in such a way that the apps themselves shouldn’t be different, but it was worth testing all the same. Games ran just fine, no apps crashed, and everything was very much business as usual.

I wandered through a few forums to see if anyone was having problems with specific apps, but when I installed them on my phone I found no issues. ART, by and large, is just as stable as Dalvik.

The biggest difference I noticed with ART was in terms of battery life, which is something that should make any smartphone user happy. In our battery tests with the Nexus 5, I found that the phone was capable of getting you through a whole day as long as you only had the screen on for about three and a half hours total. This isn’t bad, but it’s also not great. With ART running I found that the screen-on experience is still very much the same. If you’ve got more than three hours of screen-on time, there’s a good chance your phone is almost dead. The difference is in how the phone consumes battery in an idle state. With ART running, the Nexus 5 could easily go a full 24 hours of idling and performing casual tasks, while with Dalvik running that same workload would only get the phone to 17 or 18 hours.

Ultimately, ART is not going to wildly change your phone just yet. This is something Google has been working on for a little while now, and it’s something that will eventually become the default runtime for Android. This is a really great thing for the future, when Android as an OS can be optimised to take advantage ART, but right now it’s not going to offer you any kind of mind-blowingly different experiences. Still, it never hurts to poke around and play with new things. As I see no negatives to running ART, I don’t think I’ll be going to back to Dalvik on this Nexus 5.

For more on ART, see our article on how Google's Dalvik replacement will be a major performance boost for Android.