Android M debuted with the usual list of features that every major OS revision has. The smaller features certainly take up the bulk of the changelog, with UI improvements and other tweaks filling the list, as well as a handful of major features too. Arguably the two biggest new features are Google Now on Tap and Doze, both of which bring about some big changes to how Android works. While Google Now on Tap is designed to bring Google's incredible informational grasp closer to your fingertips than ever before, Doze is designed to keep the battery in your phone trucking on longer than ever before. We've gone over how Doze works but we haven't really had the chance to see it in real life circumstances until now.
Google touted 2x standby time on the Nexus 9 with Doze enabled on Android M, a figure that's likely to excite anyone who gets the Android M update in the future. But what about smartphones which are generally used far more than tablets? Since Doze works best in standby mode it fits a tablet mentality much better than a phone, but that doesn't mean a phone is never in standby. Plenty of people walk around with their phones in their pockets or bags for long periods of time, and it's this time that Doze will be hard at work, keeping apps asleep and your battery percentage high. Computerbase.de put the Nexus 5 through its paces, or rather just left it alone for a very long time on the newest Android M preview build, and compared it with the same Nexus 5 running Android 5.1 Lollipop.
The results were astounding, to say the least. In an 8 hour period the results weren't quite as impressive, with Lollipop draining 4% of battery while M only drained 1.5%. These results become exponentially more impressive as time goes on, and after a 48 hour period the Lollipop Nexus 5 lost 24% while the M-powered Nexus 5 only lost 9%. 9% is insane for any phone after two whole days, and this was with syncing enabled and plenty of apps installed too, so it's not just some bare-bones test with unrealistic results. Projected standby time for Lollipop on a Nexus 5 is around 200 hours, while M-powered Nexus 5's are looking at around 533 hours total, a 2.7x improvement in standby time. Google may be offering Doze functionality per-app as well, which could give even better results depending on apps installed.