Question Firefox high CPU AND RAM usage

Please provide comments and solutions that are helpful to the author of this topic.

Kiss

Level 4
Thread author
Verified
Well-known
Oct 6, 2021
173
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?
 

Bot

AI-powered Bot
Apr 21, 2016
5,227
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.
 
Mar 4, 2022
92
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.
 

oldschool

Level 85
Verified
Top Poster
Well-known
Mar 29, 2018
8,124
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.
 

Kiss

Level 4
Thread author
Verified
Well-known
Oct 6, 2021
173
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.
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)
 

lokamoka820

Level 30
Verified
Well-known
Mar 1, 2024
1,958
I downloaded it from the Mozila website. i5-14400F - 4060TI 8GB - 32GB RAM 3200mhz
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.
 

oldschool

Level 85
Verified
Top Poster
Well-known
Mar 29, 2018
8,124
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)
Try Brave, if you want a chromium alternative closer to FF.
 

zidong

Level 2
Jul 15, 2024
71
High CPU usage when watching 4k/8k videos in youtube? Probably missing AV1 Video Extension.
 

lokamoka820

Level 30
Verified
Well-known
Mar 1, 2024
1,958
@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
 
Last edited by a moderator:

Marko :)

Level 26
Verified
Top Poster
Well-known
Aug 12, 2015
1,572
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
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?
Great new; can you do the same for RAM?
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.
 

Parkinsond

Level 23
Dec 6, 2023
1,234
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.
I am waiting for the PC to die in order to get a new one 😁
 

lokamoka820

Level 30
Verified
Well-known
Mar 1, 2024
1,958
Great new; can you do the same for RAM?
You can manage memory cache size (in KB) with the "browser.cache.memory.capacity" in "about:config".
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?
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.
 
  • Like
Reactions: Parkinsond

Parkinsond

Level 23
Dec 6, 2023
1,234
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.
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.
 
  • Like
Reactions: lokamoka820

lokamoka820

Level 30
Verified
Well-known
Mar 1, 2024
1,958
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.
You can disable memory cache by changing "browser.cache.memory.enable" to "false" in Firefox.
 
  • Like
Reactions: Parkinsond

About us

  • MalwareTips is a community-driven platform providing the latest information and resources on malware and cyber threats. Our team of experienced professionals and passionate volunteers work to keep the internet safe and secure. We provide accurate, up-to-date information and strive to build a strong and supportive community dedicated to cybersecurity.

User Menu

Follow us

Follow us on Facebook or Twitter to know first about the latest cybersecurity incidents and malware threats.

Top