Try restarting the computer. If the problem still persists, clear all cookies, cache, and history from the browser. Why don't you defragment your harddrive as well. As a last resort: uninstall the program and reinstall it.

Thanks for the reply, but I hardly think that restarting my computer every 30 minutes is an adequate solution to the problem. Firefox should NOT be using so much memory. My hard drive is defragmented automatically once a week. It is currently 0% fragmented, so that's not it.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

• https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes

I'm running Firefox 8.0.1, no add-ons, no themes, no bells or whistles. Firefox takes up large amounts of my memory and brings my computer to a crawl. I'm well educated in A+ Network+ and Cisco CNA I am by far a very educated user and can not solve this problem myself.

I hate to say it, but Firefox is slipping in quality and I may have to switch to Opera if this problem can not be resolved. It's been an issue since v.5 and continues to be a pain.

Surely you jest! Firefox 7 and now 8 were supposed to address memory issues, but also in my case, with 11 tabs open, FF 8..0.1 is using 685MB RAM, and we get periodic "Firefox 8 is using excessive RAM..." OS messages, almost one such "warning" every session.

Obviously, FF 8 has a memory leak or other memory consumption problem, one that needs to be addressed. FF 8 especially was to have addressed memory problems, but so far has not done so.

I agree, 5 yrs ago I fell in LOVE with FF b.c it was seamless, so easy going, I never had issues and ran a dozen+ add ons, NEVER a problem that was not easy for a novice like me to solve. The last 2 or so yrs has been a steady decline of issue after issue. Now after 8 I am down to barely using it and am slowly but surely going over to Chrome. My memory usage is out of this world now all of a sudden CPU is stalling the whole system at 100%, up and down...up and down... it is the most frustrating browser I have now, even more so than IE, and I cant believe I said that.

Sorry, but in my experience there is no way that FF8 has addressed any memory hogging issues.

If anything, the problem has gotten worse, with memory usage up to a ridiculous 1.1 GB. That's with just two or three tabs open, running the standard theme and with very few add-ons installed.

Of course, my PC slows down to a crawl as a result.

Shutting down FF every couple of hours (and then making sure it really is stopped via the Task Manager) is a solution, but it's also a complete pain.

As a previous big fan of FF, I really don't want to switch over to Chrome, but sadly it looks like that could now be inevitable.

Firefox has a tool called about:memory to see how your memory is being allocated. You can type about:memory into your location bar and press enter. This gives you a list of what parts of Firefox are using memory (and what tabs are in particular). Do that and see where the bulk of the memory usage is and maybe we can help figure out what's wrong.

Despite the efforts to fix the memory problems of Firefox I don't notice much improvement in the recent versions. I usually keep the browser running for days and I keep a lot of tabs. When I close most of these tabs the browser does not release much memory. At the moment I use two tabs only - this page and about:memory. According to Task Manager (Private Working Set) the memory usage of firefox.exe is ~447000 KB. about:memory reports the following:

321.93 MB (100.0%) -- explicit

├──187.61 MB (58.27%) -- js

│ ├───80.76 MB (25.09%) -- gc-heap-chunk-dirty-unused

│ ├───77.29 MB (24.01%) -- compartment([System Principal], 0x4057000)

│ │ ├──34.54 MB (10.73%) -- gc-heap

│ │ │ ├──14.90 MB (04.63%) -- objects

│ │ │ ├──10.12 MB (03.14%) -- arena-unused

│ │ │ ├───7.96 MB (02.47%) -- shapes

│ │ │ └───1.57 MB (00.49%) -- (4 omitted)

│ │ ├──19.06 MB (05.92%) -- mjit-code

│ │ ├───8.15 MB (02.53%) -- scripts

│ │ ├───5.91 MB (01.84%) -- string-chars

│ │ ├───4.80 MB (01.49%) -- object-slots

│ │ ├───3.47 MB (01.08%) -- property-tables

│ │ └───1.36 MB (00.42%) -- (3 omitted)

│ ├────6.63 MB (02.06%) -- (21 omitted)

│ ├────4.89 MB (01.52%) -- compartment(atoms)

│ │ ├──2.54 MB (00.79%) -- string-chars

│ │ └──2.34 MB (00.73%) -- gc-heap

│ │ └──2.34 MB (00.73%) -- (4 omitted)

│ ├────4.00 MB (01.24%) -- stack

│ ├────2.43 MB (00.76%) -- compartment

│ │ └──2.43 MB (00.76%) -- (8 omitted)

│ ├────2.13 MB (00.66%) -- runtime

│ │ ├──2.00 MB (00.62%) -- atoms-table

│ │ └──0.13 MB (00.04%) -- (1 omitted)

│ ├────2.07 MB (00.64%) -- compartment

│ │ └──2.07 MB (00.64%) -- (8 omitted)

│ ├────2.07 MB (00.64%) -- gc-heap-chunk-admin

│ ├────1.99 MB (00.62%) -- compartment

│ │ └──1.99 MB (00.62%) -- (7 omitted)

│ ├────1.71 MB (00.53%) -- compartment

│ │ └──1.71 MB (00.53%) -- (7 omitted)

│ └────1.63 MB (00.51%) -- compartment

│ └──1.63 MB (00.51%) -- (8 omitted)

├───85.35 MB (26.51%) -- heap-unclassified

├───35.85 MB (11.14%) -- storage

│ └──35.85 MB (11.14%) -- sqlite

│ ├──25.42 MB (07.90%) -- places.sqlite

│ │ ├──25.12 MB (07.80%) -- cache-used [4]

│ │ └───0.30 MB (00.09%) -- (2 omitted)

│ ├───8.15 MB (02.53%) -- urlclassifier3.sqlite

│ │ ├──8.07 MB (02.51%) -- cache-used

│ │ └──0.08 MB (00.02%) -- (2 omitted)

│ └───2.28 MB (00.71%) -- (12 omitted)

├────6.71 MB (02.09%) -- images

│ ├──6.03 MB (01.87%) -- content

│ │ ├──6.03 MB (01.87%) -- used

│ │ │ ├──5.27 MB (01.64%) -- uncompressed-nonheap

│ │ │ └──0.76 MB (00.24%) -- (2 omitted)

│ │ └──0.00 MB (00.00%) -- (1 omitted)

│ └──0.68 MB (00.21%) -- (1 omitted)

├────2.81 MB (00.87%) -- layout

│ ├──1.82 MB (00.57%) -- arenas

│ └──0.99 MB (00.31%) -- (1 omitted)

├────2.21 MB (00.69%) -- spell-check

└────1.39 MB (00.43%) -- (4 omitted)

Other Measurements

 0.48 MB -- canvas-2d-pixel-bytes
 0.00 MB -- gfx-d2d-surfacecache
 0.00 MB -- gfx-d2d-surfacevram
 0.01 MB -- gfx-surface-image
 6.47 MB -- gfx-surface-win32

285.29 MB -- heap-allocated 395.56 MB -- heap-committed

 3.34 MB -- heap-dirty

338.71 MB -- heap-unallocated

       2 -- js-compartments-system
      27 -- js-compartments-user

127.00 MB -- js-gc-heap

15.22 MB -- js-gc-heap-arena-unused
 0.00 MB -- js-gc-heap-chunk-clean-unused
80.76 MB -- js-gc-heap-chunk-dirty-unused
  75.57% -- js-gc-heap-unused-fraction

451.23 MB -- private 463.71 MB -- resident

 1.38 MB -- shmem-allocated
 1.38 MB -- shmem-mapped

826.39 MB -- vsize

I've used 'about:memory' before, although some of it doesn't mean a lot to me.

However, looking at the 'compartment' entries, it seems that previously viewed pages and previously closed tabs are still using lots of memory (hence the temporary fix of shutting down FF altogether).

I have FF set to automatically clear the cache each time it shuts down, so these should just be pages and tabs from the current session.

Also, just over a third of the huge 1.2 GB memory usage is down to 'heap-unclassified':

1,208.79 MB (100.0%) -- explicit

├────674.73 MB (55.82%) -- js

│ ├──137.42 MB (11.37%) -- (120 omitted)

│ ├──117.65 MB (09.73%) -- compartment

│ ├──108.96 MB (09.01%) -- compartment

│ ├───61.12 MB (05.06%) -- compartment

│ ├───44.19 MB (03.66%) -- compartment

│ ├───26.72 MB (02.21%) -- compartment

│ ├───24.17 MB (02.00%) -- compartment

│ ├───18.32 MB (01.52%) -- compartment

│ ├───18.31 MB (01.52%) -- compartment

│ ├───14.49 MB (01.20%) -- compartment

│ ├───13.79 MB (01.14%) -- compartment

│ ├───13.53 MB (01.12%) -- compartment

│ ├───13.21 MB (01.09%) -- compartment

│ ├───10.76 MB (00.89%) -- gc-heap-chunk-dirty-unused

│ ├───10.23 MB (00.85%) -- compartment

│ ├────9.45 MB (00.78%) -- compartment

│ ├────8.45 MB (00.70%) -- compartment

│ ├────8.37 MB (00.69%) -- compartment(atoms)

│ ├────7.83 MB (00.65%) -- compartment

│ └────7.76 MB (00.64%) -- compartment

├────406.82 MB (33.66%) -- heap-unclassified

├─────58.03 MB (04.80%) -- storage

├─────58.01 MB (04.80%) -- images

└─────11.20 MB (00.93%) -- (6 omitted)

Other Measurements

0.10 MB -- canvas-2d-pixel-bytes

0.00 MB -- gfx-d2d-surfacecache

0.00 MB -- gfx-d2d-surfacevram

0.00 MB -- gfx-surface-image

41.11 MB -- gfx-surface-win32

1,055.76 MB -- heap-allocated

1,085.56 MB -- heap-committed

2.17 MB -- heap-dirty

39.24 MB -- heap-unallocated

2 -- js-compartments-system

132 -- js-compartments-user

298.00 MB -- js-gc-heap

62.78 MB -- js-gc-heap-arena-unused

0.00 MB -- js-gc-heap-chunk-clean-unused

10.76 MB -- js-gc-heap-chunk-dirty-unused

24.67% -- js-gc-heap-unused-fraction

1,299.46 MB -- private

1,163.63 MB -- resident

1.61 MB -- shmem-allocated

1.61 MB -- shmem-mapped

1,545.83 MB -- vsize

If you have a lot of memory in compartments and you don't have the pages open (as you've opened them and then closed them), it's likely caused by leakage in extensions that interact with pages. For example, adblock plus, roboform, greasemonkey, firebug all have little leaks that cause pages to stay in memory.

Can you post a list of extension that you use (Tools > Add-ons) and try disabling as many as you can.