Firefox totally sucks when it comes to memory usage. After couple of hours of heavy browsing, the web browser starts to consume half of your system’s memory. The only way to fix this is to restart your browser, but that can be really painful if you have some important tabs and you don’t want to close them.
Mozilla claims that this is actually a feature, not a bug. Firefox caches pages, images and other elements, so that it can render the page as fast as possible. Consuming insane quantity of memory for performance isn’t favorable to anyone. Mozilla has realized the situation and have decided to take up memory problems as a priority, especially when they are trying to cram the Firefox browser into mobile platform.
Over the next few months, you can expect developers work a bit more aggressively over the memory issue. You might possibly see the difference in the upcoming version of Firefox 3. CyberNet wrote about an interesting plugin called RAMBack, which will empty useless cache and save memory.
[Via: Download Squad -> TechBlog]

wrote, on November 14th, 2007
Firefox is great and the browser of choice for me. But you are correct - it’s a freakin memory hog!!! Learn to restart your browser at least once, a couple times, a day and things will run smoother.
wrote, on November 14th, 2007
Claiming that they have no idea why Firefox uses that much memory does not inspire much confidence in Mozilla. Atleast they should allow users to set a maximum memory limit for Firefox, if such a thing is possible.
wrote, on November 14th, 2007
That’s great to hear! Firefox really sucks at memory usage, except that it’s the best!
wrote, on November 14th, 2007
I think that it’s about time that Firefox’s developers started doing something useful about Firefox’s memory hogging. IE’s better than Firefox in this case, and they(Firefox’s developers) don’t want IE to win, right?
wrote, on November 15th, 2007
it was never a problem with me. IE was the biggest headache.
wrote, on November 16th, 2007
hmm…there should be some trade offs…
wrote, on November 20th, 2007
[...] usage of Firefox 3 Beta 1 is pretty much the same as Firefox 2. I guess Mozilla’s plan on prioritizing over memory usage issue was plain talking and nothing else. Why jump to the conclusion, let’s wait for final version [...]
wrote, on November 27th, 2007
yes this is true. right now i have 200,000 mb of memory for firefox only.. though is not a very serious problem for me because i have 1gb of memory still i want this memory hog of firefox will be resolve, because everytime i want to open another application that it a lots of memory like adobe photoshop.
looking for this sooner…