Earlier this week, Microsoft made some bold claims about the battery life of its Edge browser, saying that laptops running Edge lasted much longer during video playback and used less energy during normal browsing operations than Chrome and Opera.

Opera, however, disagrees. The company has run its own tests and has written up the results: with power saving mode, Opera offered 22 percent more battery life than Edge and 35 percent more than Chrome. Unlike Microsoft, Opera has provided a lot more information about what its test did and how someone might replicate it. The test loaded a number of pages into different tabs and simulated button presses to scroll up and down.

While Microsoft hasn't yet formally responded, Edge Program Manager Kyle Pflug tweeted to point out that Opera's testing enabled not just power saving mode but also its built-in ad blocker, which is off by default. The test also compares Opera's latest developer build to Edge's current stable build. The latest Edge developer build supports ad blocking (through its extension mechanism) and makes a number of optimizations to further reduce battery drain.

Regardless, both companies seem to agree that Chrome's power consumption is the worst of the lot. If you're a mobile user, using Edge, Opera, or (on OS X/macOS) Safari for your browsing will give you much more time spent away from the wall socket. And if this marks a new era in the browser war—a move away from bragging about minuscule performance differences in favor of fighting over rather more significant differences in battery life—then we'll all end up winners, no matter which browser we use.