Is it possible to somehow determine which of my safari tabs has the most cpu usage?

NOTE: I haven't turned on any flash (i'm using a "plugin customs" extension) in my tabs so it's really hard to figure out visually which of the tabs is a cpu hog

4 Answers 4


Unfortunately you can only monitor per application/process, and even if in different tabs, it's just on the same application.

My suggestion is to close tabs and check which one was the culprit (obvious answer but probably the only way).


Chrome will do this.

I know your question is about Safari but bear with me. Chrome works slightly differenty from most web browsers in that each tab is created as a separate process rather than just as separate threads. This means that if a tab starts misbehaving or crashes then it won't bring down the whole application

This also means that you can bring up the Chrome task manager and it will tell you about the CPU and memory usage for each time.

With Safari though.... I don't think this is possible.

  • Yeah, no Task Manager in Safari, and it doesn't appear that the tabs run as separate processes: the system Activity Monitor shows many processes for Chrome when it has multiple open tabs but just one for Safari when it has multiple open tabs. May 19, 2011 at 15:34
  • @MatthewFrederick dude like I could be wrong ,, but I'm running Safari and for each web url which is one to one for a given tab (for the first time in my lifetime - via Activity Monitor - I see a separate, dedicated process). Now,,,maybe just maybe I've been hacked or my mind is playing tricks on me (I'm totally not running Google Chrome). I'm actually surprised because as I pointed out to Apple Support, this implementation is very #chromesque and may be the default tab management implementation for modern browsers going forward.
    – A-Dubb
    Jan 10, 2021 at 22:34

Safari does have Javascript Profiling and Timeline Recording. Enable display of the Develop menu and you can use these as a way to determine what in Safari is hogging CPU.


In Activity Monitor, you can mouse over the safari tasks and it will pop-up which URLs are on that task.

  • 1
    Well done - I am so glad that's been implemented. Thanks for finding this old post and making it better.
    – bmike
    Mar 12, 2015 at 13:18

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