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As an avid Firefox user since it began, I've been looking to make some under the hood changes to it, in order to optimize it for speed and performance. I'd also like to limit my RAM usage with it. Are there any settings that can help this? What can be changed in about:config that affects this?

I'd also like to know if themes or anything really boost RAM usage, as they are generally very small files to download.

 Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:7.0a1) Gecko/20110630 Firefox/7.0a1

I rarely open more than 10 tabs at once, usually 3 are open. I currently use the following extensions:

I sometimes load flash videos (Youtube) but mostly just use it for browsing pages, but changing the pages very quickly as I go.

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I've heard/experienced that firebug consumes huge amounts of resources - but it's so useful! Also, I've heard & experienced that running with insane numbers of tabs will always end in massive memory consumption with Firefox. As for now to actually get that memory consumption down, I'm not sure, hence this feedback being a mere comment. – Doc Jun 30 '11 at 23:55
Knowing your usage pattern helps too. How many tabs? What extensions are you running? How many of them? How many of your tabs are gonna have Flash videos? These questions will impact performance far more significantly than any firefox settings. – surfasb Jul 1 '11 at 10:52
@surfasb I have added more information – Simon Sheehan Jul 1 '11 at 12:37
up vote 3 down vote accepted

The biggest slowdowns are rarely come from ram usage these days. The best suggestions I think of right now are as follows.

  1. Get a Flash blocker. Either Noscript or Flashblock. Personally I like no script better. It keeps flash videos from autoloading and autoplaying. Nothing kills performance like flash videos.
  2. I'd also get a password/form fill manager, like LastPass. It's so satisfying to see a form with tons of fields and with two click, it will autofill everything with your information. Cake.
  3. If you haven't already done so, up the cache size, From what I hear in the Mozilla support forums, 500 MB is a good size. Any bigger and you are wasting time just managing what's in the cache and purging it.
  4. As an aside, a clipboard ring is handy, like Clipcube. Often times I'll run into multiple links I want to open up, but I don't want to run up more than 30 or so tabs. I can copy each one and Clipcube keeps them in a list I can bring up and paste them into firefox at my own pace.

Lastly, while there are other tweaks out there, I'm hesitant to really recommend any. A big part of performance is reliability. All it takes is one crash or one website not to load up completely and that kills all the time you've saved cumulatively.

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Increasing cache size sounds good, as I'm in no rush for disk space. I shall look into Noscript now – Simon Sheehan Jul 1 '11 at 13:20

The following is ripped from Up-to-date Tips: Increasing Firefox Performance (though I've fixed some typos and improved formatting) which don't seem that up-to-date but it might be helpful for you:

How to speed up the rendering of a page?

Add the following preference, Firefox will render the page immediately:

  • Ctrl+L to go to the URL entry
  • Type about:config to open the configuration editor
  • Right click -> New -> Integer
  • Type nglayout.initialpaint.delay as the preference name
  • Type 0 as the value
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I am assuming this will use more CPU, correct? – Simon Sheehan Jul 1 '11 at 13:17
It seems so. Also see – N.N. Jul 1 '11 at 13:21
Yes, this section i think should be noted. "Lower values will make a page initially display more quickly, but will make the page take longer to finish rendering. Higher values will have the opposite effect. " – Simon Sheehan Jul 1 '11 at 13:23

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