Starting with Chrome 57, released last week, Google has put a muzzle on the amount of resources background tabs can use.
The delay/suspension will halt resource consumption and cut down on battery usage, something that laptop, tablet, and smartphone owners can all relate.
Google says that in most cases, developers have abused timers, which often continue to work and consume resources even when the user switches to another tab.
The good news is that background tabs playing audio or maintaining real-time connections like WebSockets or WebRTC won’t be affected by the 1% CPU usage limit.
In a document released today, Google detailed future plans for background tabs throttling.
Suspend all background operations (not just timers) on mobile devices.
Web apps should be able to opt-out from some forms of aggressive throttling.
Evaluate if other actions (such as loading operations) could be throttled in background tabs.
Budget-based throttling for offscreen frames
Throttle web worker operations
Remove the opt-out and pause all background pages