Android M may finally meet the long-unfulfilled dream of better battery life first pledged with Lollipop.

A side-by-side test of two Nexus 5 phones, one running Android 5.1.1 and the other running M, show the latter outperforming Google’s promises from I/O.

According to German blog Computerbase, the Android Lollipop model lost four percent of its battery while on standby for eight hours, while the Android M edition only dropped 1.5 percent.

After 24 hours, the Lollipop unit drained 12 percent compared to only 4.5 percent for Android M. The same ratio carried out over 48 hours: the Lollipop Nexus was down 24 percent, while the Android M phone only lost nine percent of its charge.

Using this data, the blog computed an expected total standby time: 533 hours for Android M compared to 200 hours for Lollipop. Given that Android M is still in developer preview, there’s a good indication this performance may get even better as Google improves the operating system.

Computerbase.de Computerbase saw fantastic improvement in standby battery life running the Android M developer preview. (translated from German)

Even though this was only a test of standby capabilities, it’s encouraging. Battery life is increasingly important on Android because phones like the LG G4, with a removable battery, are becoming the exception. The Galaxy S6 and others are going the non-removable route, which makes squeezing every last moment of battery life key.

The story behind the story: Google announced at I/O that Android M would tackle standby battery life head-on with its Doze feature. This will determine when you’re using your device and give it cat naps during period of inactivity. After this blog’s experiment, we’re eager to see how this will impact a phone’s battery during a day of email, social media, and games.