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Firefox is making system run slow

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  • Last reply by Xircal

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Hi. I have been running firefox since it first came out. I remember it made internet explorer look like your were browsing on dialup no joke. Anyhow, with the latest firefox it runs very slow on my laptop. My laptop is older. It's a HP 6735s. I tried a different browser - Opera. Opera runs perfectly fine on this laptop but does not display everything corrects(forms,buttons). I did notice Opera uses way more memory than firefox.

Is there anything I can do to speed up firefox or make it use more memory? Currently if I try running firefox in safemode it uses at least 80% cpu usage and does the same w/o safemode. I really would like to continue using firefox as it does seem the best browser. Is my laptop too old to run firefox? Any suggestions are appreciated. Thanks!

Hi. I have been running firefox since it first came out. I remember it made internet explorer look like your were browsing on dialup no joke. Anyhow, with the latest firefox it runs very slow on my laptop. My laptop is older. It's a HP 6735s. I tried a different browser - Opera. Opera runs perfectly fine on this laptop but does not display everything corrects(forms,buttons). I did notice Opera uses way more memory than firefox. Is there anything I can do to speed up firefox or make it use more memory? Currently if I try running firefox in safemode it uses at least 80% cpu usage and does the same w/o safemode. I really would like to continue using firefox as it does seem the best browser. Is my laptop too old to run firefox? Any suggestions are appreciated. Thanks!

Chosen solution

You've written "Unsure" next to "Plugins", so the first thing to do is to check to see if any of those is out of date. To do that, go to the Plugins Check page and update where necessary. Older plugins are also a security risk.

Next, run a reputable malware scanner to see if malware or a virus is the culprit. Download the free version of "Malwarebytes" and run a full system scan. You can get it from here: http://www.malwarebytes.org/products/malwarebytes_free


Next, do some house cleaning.

  1. Clear browsing history and cache by clicking the orange Firefox button, go to History | Clear Recent History.

  2. In the menu which opens, change it to "Everything" at the top and then click the arrow below that and remove the checkmarks from "Form and Search History" (fills in forms automatically), "Cookies", "Automatic Logins" and "Site Preferences".

  3. That leaves just "Browsing and Download history" and "Cache" checkmarked. Then click the "Clear Now" button. It may take a few minutes to delete, so be patient.


How many Add-ons do you have installed? Check by clicking the orange Firefox button, click Add-ons, then Extensions. If you have any of the ones on this list, remove them: https://addons.mozilla.org/en-US/firefox/performance/ But more than 10 Add-ons will start to degrade performance especially on an older machine.

Check the "Problematic Add-ons" list for others known to cause problems @ http://kb.mozillazine.org/Problematic_extensions

Hope this helps.

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Chosen Solution

You've written "Unsure" next to "Plugins", so the first thing to do is to check to see if any of those is out of date. To do that, go to the Plugins Check page and update where necessary. Older plugins are also a security risk.

Next, run a reputable malware scanner to see if malware or a virus is the culprit. Download the free version of "Malwarebytes" and run a full system scan. You can get it from here: http://www.malwarebytes.org/products/malwarebytes_free


Next, do some house cleaning.

  1. Clear browsing history and cache by clicking the orange Firefox button, go to History | Clear Recent History.

  2. In the menu which opens, change it to "Everything" at the top and then click the arrow below that and remove the checkmarks from "Form and Search History" (fills in forms automatically), "Cookies", "Automatic Logins" and "Site Preferences".

  3. That leaves just "Browsing and Download history" and "Cache" checkmarked. Then click the "Clear Now" button. It may take a few minutes to delete, so be patient.


How many Add-ons do you have installed? Check by clicking the orange Firefox button, click Add-ons, then Extensions. If you have any of the ones on this list, remove them: https://addons.mozilla.org/en-US/firefox/performance/ But more than 10 Add-ons will start to degrade performance especially on an older machine.

Check the "Problematic Add-ons" list for others known to cause problems @ http://kb.mozillazine.org/Problematic_extensions

Hope this helps.