Firefox is a free to use open source web browser developed by The Mozilla Foundation. FireFox is available for Windows, Linux, and Android and was released in November of 2004. The browser has a lot of users due to its easy to use and fast infrastructure. Sometimes, users encounter a problem in which Firefox uses too much memory and becomes sluggish compared to its previous performance. This problem persists even if there are only a couple of tabs open on the browser.

What Causes Firefox to Use a lot of Memory?
We investigated the matter once we received several reports from a lot of users and came up with a set of solutions that had solved the issue for a number of users. Also, we looked into the cause of the problem and devised a list of potential culprits due to which the problem might be triggered.
- Extensions/Themes: If you have installed any extensions or custom themes on the browser it is possible that they might be using more memory due to certain modifications that come with them. Sometimes, the extensions can get installed automatically on the browser if you visit a certain site or install a certain program on your computer. These extensions might be malicious or dangerous to the integrity of your computer’s security as well.
- Disabled Hardware Acceleration: There are often advertisements on many websites that you might visit and they play Flash Content. Flash content requires a memory draw in order to load. However, the hardware Acceleration feature inside the Firefox browser can reduce the stress on your Memory if a dedicated graphics card is installed on your system.
- Excessive Tabs: If you open a lot of tabs and on each tab, a website is loaded it increases the memory usage. Therefore, excessive tabs increase the memory draw from the system.
- Outdated Software: It is possible that the version of the Firefox browser that you are using is old. In each update to the browser, the company provides important improvements and bug fixes which ensure a smoother experience for the user.
Now that you have a basic understanding of the nature of the problem we will move on towards the solutions. It is recommended that you implement these in the specific order that they are provided in.
Solution 1: Restarting the Application
If you have been using the browser for extended periods of time and a couple of tabs have been open for a while, it can increase the usage of memory. Therefore, it is recommended to completely refresh the application by restarting it. This helps reinitialize the browser and helps in decreasing memory usage.
Solution 2: Disabling Custom Extensions/Themes
If you have installed any extensions or custom themes on the browser it is possible that they might be using more memory due to certain modifications that come with them. Therefore, in this step, we are going to disable all the extensions and themes. For that:
- Click on the “Menu” button on the top right and select the “Add–ons” option from the list or press “Ctrl+Shift+A” to open it directly.
- Now click on the “Extensions” option on the left side.
- Once the list of extensions loads, click on “Disable“.
- Now click on the “Theme” option on the left side.
- Click on “Enable” in front of the “Default Theme” option.
Solution 3: Enabling Hardware Acceleration
Flash content requires a memory draw in order to load. However, the hardware Acceleration feature inside the Firefox browser can reduce the stress on your Memory if a dedicated graphics card is installed on your system. Therefore, in this step, we are going to be making sure that the Hardware Acceleration feature is enabled. For that:
- Click on the “Menu” button on the top right side and select “Options” from the list.
- Click on the “General” button on the left side of the window.
- Scroll down to the “Performance” settings heading.
- Uncheck the “Select Automatically” box.
- Now make sure that the “Hardware Acceleration” box is checked.
- Use the default allocated “Content Process limit“.
Note: Only enable this option if you have a dedicated graphics card installed on your computer because this option enables the use of the dedicated graphics card to load flash content instead of the processor and memory.
Solution 4: Updating the Application
It is possible that the version of the Firefox browser that you are using is old. In each update to the browser, the company provides important improvements and bug fixes which ensure a smoother experience for the user. Therefore, in this step, we are going to be checking for updates to the browser and installing them if available. For that:
- Click on the “Menu” button on the top right corner and select “Options” from the list.
- In the options, select “General” from the left side.
- Scroll down to the “Firefox Updates” heading.
- Click on the “Check For Updates” option.
- After the browser finishes downloading the update, click on the “Restart Firefox to install the update” option.