Google is releasing Chrome 57 this week with further power reductions. The company claims background tabs "consume a third of Chrome's power usage on desktop," so there is space for power optimizations.
Starting in version 57, Chrome will throttle individual background tabs by limiting the timer fire rate for background tabs using excessive power.
Like many browsers, Chrome has also limited timers in the background to only run once per second. Via the new throttling policy, Chrome 57 will delay timers to limit average CPU load to 1% of a core if an application uses too much CPU in background. Tabs playing audio or maintaining real-time connections like WebSockets or WebRTC won't be affected.
Google says that this throttling mechanism leads to 25% fewer busy background tabs. In the long-term, the ideal is for background tabs to be fully suspended and instead rely on new APIs for service workers to do work in the background.
Last year, Microsoft started "a battery life war" with Google's Chrome browser and since then, Google has been responding.
Google promises to "continue to take steps in this direction to prolong users' battery life" in future Chrome releases.