Google has been working hard on Chrome to deliver better battery efficency as the browser’s been known to kill many a laptop in it’s day. Luckily, with version 57, it looks to get even more efficient by throttling background tabs.
Specifically, if a tab has been untouched for more than 10 seconds, Google will limit how much of your CPU it can sip, therefore cutting back energy consumption and resulting in (at least according to Google) 25% more efficiency. This feature is great for those who tend to leave lots of tabs open in Chrome and forget about them. I can testify to this claim as I constantly make this battery-draining mistake.
For reference, if you have, say, music playing within a tab or a messaging service open like Hangouts or Facebook Messenger, Chrome won’t throttle their respective tabs.
Google Chrome v57 is now rolling out to all desktop users.