Chrome's Page visibility API checks tabs after 10 seconds in the background. The new feature will leave tabs playing audio or maintaining WebSockets or WebRTC connections alone, since the API considers them to be in the foreground. However, it minimizes all the tabs the API considers to be in the background unless it's absolutely necessary to run them at full capacity.

The Chrome team says this new mechanism can lead to 25 percent fewer busy background tabs. Since their goal is fully suspend those tabs, though, their work is far from done. Chrome 57 has been out for a few days now. You can download it anytime, especially if you're always on the go and would like to limit Chrome's impact on your laptop.