We all know just how much CPU and especially RAM that Chrome can eat up, but Google promises that Chrome 57's background tabs will be limited to an average CPU load of just 1%, on a single CPU core.
Google explains the throttling method that they've used on background tabs on their Developers website, with Google pushing every background tab into its own time budget (in seconds), with specific CPU time for the tab to complete its process - and is limited to just 10 seconds, freeing up CPU cycles. The company does note that the regeneration code can be shifted around, as they take in more data about how background tabs are throttled.
If you're like me - right now, you've got a background tab playing music through Google Play Music, so there will be some exceptions to background tab throttling in order to see those tabs not crashing or not functioning properly.
Google said that background tabs use around 1/3 of Chrome total power usage on a PC, so we can expect some big power savings here. Google's awesome Chromium team said that they're seeing "25 percent fewer busy background tabs", which is music to my ears, at least.