Solved Firefox high CPU AND RAM usage

Kiss

Kiss

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Hi, I started using Firefox a few days ago and noticed the high CPU and RAM consumption, I compared it with Chrome and Edge and with 5 open abs, Firefox consumes over 1GB of RAM, while Chrome and Edge only 600MB RAM, something else It's CPU usage, Firefox uses more CPU on YouTube videos and websites too, is it just on my system or has anyone else seen this?
 
This is a known issue with Firefox. It often uses more CPU and RAM than other browsers due to its multi-process architecture. You can try reducing the number of content processes in Firefox settings, disable unnecessary extensions, or use the built-in task manager to identify high usage tabs and close them.
 
Open Firefox's task manager to see where are the resources are going: Shift+Esc

On my PC, if I have one tab open, Firefox uses at least 100 MB of RAM more than Brave (don't have chrome), but that is most likely because I have ad/tracker blockers on Firefox and Brave has those built in. My PC is powerful enough to not notice any difference when using them.
 
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That sounds high. I have Firefox with one open tab 400MB vs Edge with 4 open tabs @ 500MB and Brave with 5 open tabs @ 450MB. My experience is that FF just uses more RAM. Have you tried restarting your machine? I found that restarting often fixes little glitches like that.
 
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oldschool said:
That sounds high. I have Firefox with one open tab 400MB vs Edge with 4 open tabs @ 500MB and Brave with 5 open tabs @ 450MB. My experience is that FF just uses more RAM. Have you tried restarting your machine? I found that restarting often fixes little glitches like that.
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It's no use, I tried everything, unfortunately Firefox on my system didn't work, I went back to Edge, light and fast. thank you everyone. (y)
 
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Kiss said:
I downloaded it from the Mozila website. i5-14400F - 4060TI 8GB - 32GB RAM 3200mhz
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Nice, so the problem is not with your Firefox version nor with your PC specifications, I will not say it is lighter or heavier than other browsers, but with your PC it should run smoothly.

If you noticed high CPU usage with Firefox, try to close it, and check from task manager if all Firefox instances closed, I sometimes noticed that it stuck in the background and CPU usage continue to rise, try ending the task then open Firefox, it will work normally.
 
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@Marko :) I found that disabling Firefox disk cache working properly and back to use Firefox again, I just discovered about "about:cache" which shows that cache is not saved on my disk:

2025-05-25 at 22-35-13 firefox.png2025-05-25 at 22-34-13 firefox.png
 
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lokamoka820 said:
UPDATE:

@Marko :) I found that disabling Firefox disk cache working properly and back to use Firefox again, I just discovered about "about:cache" which shows that cache is not saved on my disk:

View attachment 288773View attachment 288772
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How did you get to this? Also, can you tell me where did you disable disk cache? I increased 1500000 as it was recommended on the internet; is there anything else I should disable?
Parkinsond said:
Great new; can you do the same for RAM?
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If 8 GB isn't enough for you, just get more RAM and don't worry about it.

RAM's lifetime isn't affected by using it, unlike that's the case with SSDs.
 
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Marko :) said:
How did you get to this? Also, can you tell me where did you disable disk cache? I increased 1500000 as it was recommended on the internet; is there anything else I should disable?

If 8 GB isn't enough for you, just get more RAM and don't worry about it.

RAM's lifetime isn't affected by using it, unlike that's the case with SSDs.
Click to expand...
I am waiting for the PC to die in order to get a new one 😁
 
Parkinsond said:
Great new; can you do the same for RAM?
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You can manage memory cache size (in KB) with the "browser.cache.memory.capacity" in "about:config".
Marko :) said:
How did you get to this? Also, can you tell me where did you disable disk cache? I increased 1500000 as it was recommended on the internet; is there anything else I should disable?
Click to expand...
I just changed "browser.cache.disk.enable" to "false" in "about:config" yesterday, and checked the result in "about:cache", watched videos for 4 hours continuously writes 1 GB to SSD.

Today I changed "browser.sessionstore.interval" to "1800000" (the default is: 15000 milliseconds) in "about:config", it writes about 500 MB for 3 hours of browsing (2.5 hours of that watching videos).

In clear browsing data "cache files" always shows "0", I even checked with 3rd party disk cleaners.
 
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lokamoka820 said:
You can manage memory cache size (in KB) with the "browser.cache.memory.capacity" in "about:config".

I just changed "browser.cache.disk.enable" to "false" in "about:config" yesterday, and checked the result in "about:cache", watched videos for 4 hours continuously writes 1 GB to SSD.

Today I changed "browser.sessionstore.interval" to "1800000" (the default is: 15000 milliseconds) in "about:config", it writes about 500 MB for 3 hours of browsing (2.5 hours of that watching videos).

In clear browsing data "cache files" always shows "0", I even checked with 3rd party disk cleaners.
Click to expand...
Looked for a similar tweak in Edge and Chrome with no luck.
Caching, although destructive for SSD, but has benefits like speeding browsing and reducing bandwidth consumption.
 
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Parkinsond said:
Not using Firefox; its RAM usage is more than any chromium browser.
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Firefox has a built-in memory tool that can troubleshoot any issue specific to memory.

Open a new tab and type "about:memory", then press Enter. Under "Free memory", click the "Minimize memory usage" buttons to reduce Firefox memory usage on your PC.
 
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