See this. https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

Note that Windows sometimes report a wrong total disk usage for applications.

You can check the disk usage in these locations for the main profile folder and for other cache files:

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\
• C:\Users\<user>\AppData\LocalMozilla\Firefox\Profiles\<profile>\

Note that the "AppData" folder in Windows Vista and later Window 7+ versions and the "Application Data" folder in XP/Win2K are hidden folders.

• http://kb.mozillazine.org/Show_hidden_files_and_folders

ooo i wouldn't call this wrong......... the one that is located in app data "local" (C:\Users\sharif\AppData\Local\Mozilla)its 1.38gbs

i am not sure if this is related but i noticed it fills up quickly when i use sites like YouTube

i did mention its not a ram issue :P

Start Firefox in Safe Mode
While you are in safe mode;
Firefox Options > Advanced > General.
Look for and turn off Use Hardware Acceleration.
Poke around safe web sites and see if there is still a problem. Then restart

Sorry if I misunderstood. In this case, however, you can set Firefox cache size to suit your needs

i already tried turning hardware acc off but no difference but addons disable start up helps and makes it feel more responsive ooh yeah firefox size increased to 3+gbs

No problem And how do i do this?

Firefox Options > Advanced > Network.

thanks it will be useful for future reference

Firefox have started to get slugish

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• TDSSKiller - AntiRootkit Utility
• Hitman Pro
• ESET Online Scanner

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Did this fix your problems? Please report back to us!

i use avast internet security and i am aware of what i download and install i would have been aware i already did a full scan

oh yeah i switched to chrome i again its way better and smoother

Which of its sub folder(s) is/are the largest?

Is that the thumbnails folder or one of the others like the Cache?

You can delete all the folders in the cache location in AppData\Local to remove all stored data.

C:\Users\sharif\AppData\Local\Mozilla\Firefox around 700mb cache 1 and 2 are the largest and i can't delete them,as all the bookmarks and plugins are there i think* my hard drive is currently 3.7gbs less then its supposed to be becasue after i clear cache mt hard drive goes back to 10.9 free while now its 7.3 free

How is configured your Firefox browser cache size? There is a certain value, or to manage the browser?

update

i reseted all the option (about:config)and updated all apps like java,flash etc (both 64 and 32bit) and will see if they are all back to normal