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Firefox is blocking my 12 GB of RAM

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A few days ago, my 64 bit Windows 7 Pro running PC started to latch up when I open Firefox. In Task Manager/Performance I see all my 12GB of RAM occupied. If I do not start Firefox, my PC is using only 2.900 GB of RAM. I tried to install Firefox again, using the 327 kB application, downloaded recently from Mozilla and the problem persists. I closed about 25 tabs from those four windows I have opened with no result. I am using now Waterfox and Pale Moon, shall I move everything in those two browsers and quit using Firefox, even if it is my favorite browser? I do not want to use any Google-based browser. Please excuse my poor English and help me. Thank you very much.

A few days ago, my 64 bit Windows 7 Pro running PC started to latch up when I open Firefox. In Task Manager/Performance I see all my 12GB of RAM occupied. If I do not start Firefox, my PC is using only 2.900 GB of RAM. I tried to install Firefox again, using the 327 kB application, downloaded recently from Mozilla and the problem persists. I closed about 25 tabs from those four windows I have opened with no result. I am using now Waterfox and Pale Moon, shall I move everything in those two browsers and quit using Firefox, even if it is my favorite browser? I do not want to use any Google-based browser. Please excuse my poor English and help me. Thank you very much.

Chosen solution

Can you compare two different lists:

(1) Windows 7 Task Manager (Ctrl+Shift+Esc), Processes tab

(2) Firefox's about:processes page

This should allow you to determine which tabs are using the most memory. Can you account for it, or is there excess memory use not listed on about:processes?

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All Replies (5)

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Chosen Solution

Can you compare two different lists:

(1) Windows 7 Task Manager (Ctrl+Shift+Esc), Processes tab

(2) Firefox's about:processes page

This should allow you to determine which tabs are using the most memory. Can you account for it, or is there excess memory use not listed on about:processes?

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Thank you for your kindness. Meanwhile, I managed to solve the problem by entering Properties of Firefox desktop shortcut and roll back to a previous version, a restore point from June 2020. Now I have opened in Firefox 4 windows with a total of about 35 tabs and my PC uses a total of 4.65 GB of RAM. I will take care to avoid any update to Firefox, even if it bothers me to do it. I hope it will be possible to continue using Win7Pro, I do not like neither Win10, nor Win11. Thanks again. Best regards, Adrian.

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I suggest still investigating the high RAM usage as suggested previously. Some sites may require a lot of memory, but over 4GB sounds surprisingly high.

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Without Firefox, my PC uses about 2.8 GB of RAM. With Firefox, in a few hours, RAM usage increased to 11.5 GB without opening new tabs or windows, I am just an amateur without many skills, so I have chosen the the radical solution: I will give up using Firefox, I will try to find other convenient Firefox-based browsers, maybe I will try Microsoft Edge, even though people say it wants to know too much. Thank you again. Best regards, Adrian.

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Okay, but meanwhile, that sounds suspicious to me so I suggest some malware scans to check whether your system is infected. The following support article suggests tools other users have found helpful: Troubleshoot Firefox issues caused by malware.