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Browser Memory Test: Firefox vs IE7 vs Safari vs Flock vs Opera

Last time when I wrote a post on how to save IE from attacks, all my readers were of the opinion that Firefox should be used instead of using IE7. We all know the fact that Firefox consumes lot of memory while running. With 5-6 tabs open, Firefox was consuming lot of memory for me, so I decided to check which browser was best in terms of memory consumption.

Browsers tested:

  • Firefox
  • IE 7
  • Flock
  • Opera
  • Safari

Popular Browsers

In order to test the browsers, I opened only 2 websites, one was this blog and other was Google search page. Here are the results;

1. Firefox

Memory used: 59 MB


2. Flock

Memory used: 58 MB


3. Opera

Memory used: 35 MB


4. IE7

Memory used: 49 MB

Internet Explorer

5. Safari

Memory used: 53 MB


Firefox was the one which consumed maximum memory and Opera the least. Opera is definitely the best in terms of memory consumption, but the fact that it does not have much options in terms of add-ons like Firefox or Flock makes it less popular compared to Firefox. Flock is also a good option considering the fact that its build on Firefox platform and also supports most of the Firefox add-ons. The latest version of Safari is much stable and consumes less memory.

About Nirmal

Nirmal is a Technology Blogger and a Microsoft MVP in Windows. He can be contacted at nirmal@nirmaltv.com. You can find Nirmal on , and .


  1. Firefox definitely uses up a lot of memory but the reason could be some of the extensions too. I use firefox with a profile which has no extensions installed and it works perfect consuming less memory.

    I have not use Opera though but use both IE7 and Firefox and feel IE7 performs quite good when it comes to memory usage.

    The best thing to do for consuming less memory is regulalry clearing the cache in Firefox.

    BTW I was curious whether you conducted these tests using the same tabs open in all the browsers?

  2. Firefox is definitely a hog. What’s worse is that just a couple versions back, it had a lot of memory issues. Sometimes, I would notice it using 500MB+ of memory if I’ve had it open for a long time and had visited a lot of sites (which is the norm for me).

  3. @Keith,
    The memory of Firefox could be with those extension also, but I have least number of extensions. Even IE also has the same number of extensions.

    All the browsers were tested for same number of tabs and same websites and no other window was open. All under same conditions.

    Lets hope that the new version will be much better in terms of memory.

  4. How long was the tabs kept open? When you open Firefox for a longer period of time, the memory goes up exponentially. It takes 120+ MB if opened for a day or so.

    Opera might not have Add ons as Firefox but has a lot of features that FX doesn’t has. We need extension for them.

    Safari also has a lot of features than Firefox and the good thing is it’s supporting add ons! Popular Add Ons in Firefox like ABP, Greasemonkey is already there in Safari now.

    I use FX, only for the extensions and it’s days is numbered if they don’t fix the memory issue. I’ve 3 GB RAM at my disposal yet I like to use Safari if more features and add ons are there. Also Safari for Mac has more features and better than Safari for Windows.

  5. @Ashwin,
    You got a valid point there, regarding the time it was open. All the browsers were open only for a few minutes until the memory consumption was stable. FX does increase its memory consumption when you keep for more than a day.

  6. Firefox uses a lot of memory instead of 2 websites if you open many tabs and for longer period you will have different results i guess. If we dont use many extensions in Firefox it wont consume a lot of memory

  7. Good comparison there. I’ve also found that FF consumes a lot of memory, but I’m still hesitant to switch because if I do, I’m going to miss the extensions.

    On my PC, IE 7 is a big memory hog. It hangs even when one or two tabs are open and performs slowly.

  8. @Ram,
    You are right, if you keep Firefox open with too many tabs for long time, it virtually hangs Windows.

    Its very difficult to switch from Firefox. 😀

  9. @nirmal,
    It’s looking better so far. The Zend developer platform seems to be hogging memory, though. Oddly, it says it’s using 50MB, but when I closed it yesterday, I got about 400MB back, which could be a fluke.

  10. When it comes to memory, Firefox is the hungriest of all 🙁 But still, once addicted, you can’t get off it 😀

  11. I prefer IE and sometims Opera. Opera is very lightwait , as can be seen from your experiments.

  12. A few quick questions:

    1. What extensions or add-ons were in use with the browsers?
    2. Were any plug-ins being displayed? (ie Flash)
    3. What OS was this under? (I’m assuming Windows XP or Windows 2000)
    4. What were the system specifications?
    5. How long had the programs been running?
    6. Was there any sort of swap (or at least that is the Linux term) in use?
    8. What versions of Firefox, Flock, and Opera were you using? I am getting considerably less for a Firefox trunk build than Firefox 2. Firefox 1.5 is using even more (from GNU/Linux system).

    I’m just asking because I don’t see how these results are conclusive. I am getting different results that you by testing on Linux (without IE7 and Safari of course), Windows Vista, and Windows XP. It may also be the specific versions that are different.

    Also, what is the tool you are using to calculate memory usage? Different tools tend to have different results slightly, depending on how it is calculated.

  13. Oh, also, I would like to point out that on Vista Home Basic, IE7 hangs for me a lot. It literally crashes the system if I have more than 7 or 8 tags open because it consumed 98% of the memory.

  14. Recently I installed 5 browsers on my machine

    1) IE 7
    2) Firefox
    3) Safari
    4) Opera
    5) Netscape Navigator

    I know you will ask me why this many, but just to test my website design on different browsers.
    Meanwhile when I read this blog, I decided to test Navigator aswell, but it failed in your ranking. Comes around last 2, but the memory grows slowly as you keep it open for some time. Meanwhile Opera took the first position as well. Opera was the most stable, optimized software. Which has a stable memory usage and doesnt grow with time.

  15. @Jake,
    To clarify your doubts;
    1. Firefox had alexa plug and Stumble upon, IE also had 2 plugins installed, so was the case with Flock. Safari and Opera didnt have any plugins
    2. Flash was not displayed
    3. Windows XP
    4. System specification? I dont think that should matter as all are running on same specs
    5. All the browsers were tested for same time. Firefox increases its memory consumption when kept for long time.
    6. No sort of Swaps
    7. All browsers were of the latest version stable version available

    IE7 gives sometimes too much memory hog for me also. Jake remember this is not an exhaustive testing. 🙂
    But we have to agree to the fact that Opera is the lightest of all, but lack of add-ons makes it weak.

  16. @SmackAll,
    Initially I thought of installing Netscape as well, but then at the last minute, didnt add it. 🙂

  17. I got sick of FF 2, and switched to Opera with its breeze-like surfing. However, I got tired of having to adjust to a vanilla browser sans the plugins. If it weren’t for extensions, I’d be happy on Opera.

    Flock is good in that aspect, as there’s all the extensions. And Duncan Riley of techcrunch said its much better in memory and CPU usage.

    I’m gonna try Flock as soon as it hits a stable version.

  18. after couple of hour, My Firefox consume all my comp memory 🙁

  19. @Sumesh,
    Flock’s stable version is available.

  20. Nice take.

    I love FireFox but it is a real memory hog even on my System with 1.5 GB of RAM.

    Opera is also cool and I use it sometimes but, not as frequently as FireFox.

    Cheers (y)

  21. @Nirmal
    Anyway, I dont think Netscape is competing the others in any way. It lags in all tests but still bit stable then firefox. Thats all about Netscape.

  22. I suggest people look for enigma browser and download it from http://store.democratz.org

    You can find the link just above the products and you can download it for free.

    Engima runs faster than Firefox and you can easily run 32 tabs and not slow down the machine.

  23. I have been using the firefox for more than 6 years with no problems, What are you guys talking about memory, is everybody using 64MB of RAM,Then please change your system confirguration.As i was writing this, i checked my IE memory it was like 123MB.

    Memory usage largly depends on the websites which you use.ActiveX thats loaded and things like that.

    If you want your system to get attacked by virus,Frequent crashes you can very well use the IE.In that sense its really good.

    Otherwise for a good browser experience and lots of add-On features Firefox is the best.

    I would rank browser’s in this order firefox,opera,IE….

    I have used opera its just fast that you couldnot imagine.

    Support opensource guys….

  24. Nirmal,

    You are right….

    Firefox takes lot of memory. I have also noticed that when you close all the opened tabs and keep open only one tab. It still doesn’t release the memory.

    Do you know any trick to overcome this…

  25. Its true in my experience.
    Firefox takes very large memory an causing system to slow.
    But i am unable to leave using firefox due to the options like open last closed tab and in closing firefox inappropriate way,is gives option resume session.

  26. I totally agree with the originator of the post. Firefox 3 uses a lot more memory than IE. I use IE 8 Beta on both my Vista and Windows 7 machine without any problems. I would suggest IE and Opera. Opera is the fastest and eats up minimum amount of memory but some sites donot display correctly in it. So for such sites, IE is best. Just wait for IE 8 final version & install it.
    And Sundar, I have 3 GB of RAM.

  27. operachromeisbetter

    i was originally using firefox. however when i used google chrome, when i could not access a webpage with firefox, immediately i stopped firefox and i picked up chrome. just only i am trying out opera after visiting firefoxmyths.com.

    and yes i am sick of firefox fanboys

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