Background Tab Throttling — Cut Chrome CPU at Rest (2026)

When Throttle Background Activity is on, setTimeout, setInterval, and requestAnimationFrame callbacks in background tabs (where document.hidden is true) are throttled. Background tabs don’t stop working when you leave them. Scripts keep running: polling for data, ticking animation frames, executing recurring callbacks. Most of that activity is invisible to you but visible to your CPU.

What Gets Throttled

Sub-100 ms timers become 500 ms, sub-1 s become 2 s, sub-5 s become 5 s, and longer delays double up to a 10 s cap. Zero-delay timers are left unchanged. Animation frames drop to a lower rate.

The active tab: very short timers round up to 100 ms, and longer timers and animation frames are untouched. The intent is to cut background-tab CPU.

Who This Is For

The feature is most useful on machines where Chrome’s CPU usage stays high even when you’re not actively loading pages. Open Chrome’s Task Manager (Shift+Esc) and sort by CPU. If several background tabs are consistently showing nonzero CPU percentages, this toggle directly addresses that.

On machines with plenty of headroom, the difference may not be noticeable. On older hardware, constrained laptops, or sessions with 20+ tabs, reclaiming that background CPU can meaningfully improve responsiveness in your active tab.

PRO-Only

Throttle Background Activity requires a PRO license. In the popup it appears in the Tabs and memory sheet as “Lighter background tabs”, shown with a lock — “Lighter background tabs is a Pro option” — when the free tier is active.

Whitelist First

If you run a web app in a background tab that needs accurate timing (a dashboard, a communication tool, a live data view), add its domain to the whitelist before enabling this feature. Whitelisted domains are excluded from script throttling (and any other Perf feature you list in the whitelist entry). Tab suspension protects 34 web app domains automatically, but throttling does not.