MacOS – does Firefox take nearly 300MB+ of RAM just to open one tab


I have been peaking in macOS Activity Monitor and found this:

One tab spawns atleast 3 processes:

  • Firefox ~400MB
  • FirefoxCP Web Content ~200MB
  • FirefoxCP Web Extensions ~200MB


Update – ran again and got these numbers …

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Best Answer

It depends on what exactly you are running at any given time.

You have to understand how a web browser has evolved over time.

Back in the day (man i'm feeling old). Web browsers were simple pieces of software that didn't do much but show a webpage and displayed simple html code. Most people did not even know what a browser did, because a computer was mainly dependent on software for typing documents, filling out spreadsheets, or playing games that didn't require an internet connection.

Now-a-days Web browsers are way way way more complex. As society has evolved, so has our web browsers. Because society has become dependent on web browsers than any other internet based protocol.

People can build entire pieces of software that function with-in a web browser. This kind of power requires, much more powerful code, like Java (PHP), ASP, Python.. etc. And even those have evolved over the years to allow more libraries to allow web designers to do just about anything a stand alone piece of software can do.

For any webpage to be able to handle these powerful languages it has to load all the necessary libraries requires to display any given webpage. Once a page is loaded. How ever simple a webpage may look, behind the scenes, there can be a variety of complex code running in the background (using up your CPU or memory to do so) in order to allow the web page to function properly.

  • Browser extensions. This is a relatively new concept that you could add extensions to your browser, and it was almost like you had programmings running in the background of your browser in order to accomplish a specific task.

Examples: Weather extension would routinely check with the current weather status in your area. Adblock software, will check any page for harmful code or unwanted advertisements or popups.

  • Facebook, for example. There is a lot going on there. Friends list (chatting program), Your newsfeed. Maybe video is playing without any sound as you put your mouse over it. There can be groups that are active and sending you notifications as your responding to someone's post.

All that stuff going on there feels very clean and seamless, in reality it requires A LOT of computing power and many lines of code (memory usage) in order to give an acceptable modern-day user experience.

  • Websites that are basically pieces of software. Photopea is basically an exact copy of a Photoshop. Yes, Photoshop! 10 years ago, this would have never been possible. And the moment I load this website, and start a new project my memory usage goes up by 200 MB. And I haven't even start doing anything yet.

So to sum everything up. Your answer is: It Depends!

  1. It depends on what build of firefox you're running
  2. It depends on how many extensions you are using, and how active they are during your browsing activities.
  3. It depends on what webpage you are on. Going to a webpage that was built in 1996 is going to use different amounts of memory compared to a modern website such as youtube.
  4. And it could also depend any number of things i'm unaware of that is going on in the background that requires firefox, chrome or any modern web browser to function properly.

Remove all of your extensions and visit and see how much memory that takes. I bet you it'll be far less than your current setup.

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