Firefox 1.5 saw the addition of a page cache mechanism that could be responsible for Firefox's memory woes. The browser stores the last 8 pages you viewed in your computer's RAM (if you have less than a gigabyte of RAM, it stores less).

Caching pages in memory allows faster back-browsing -- meaning better performance as you navigate the web -- but this can be a lot of data and less RAM for other apps to use.

Given the rising popularity of web-based applications which require greater amounts of system resources, could it be that the web is simply getting too heavy for a svelte browser to handle?





Of course the flip side 






points out, 

Otherwise, you're having to run a browser with a zillion
plugins - and none of them aware that other plugins might be running.
You have a more stable program if said items are actually integrated
into the base.



Many of Firefox's memory usage woes come from a page cache mechanism introduced in version 1.5, the last major revision before the current version. The browser stores the last 8 pages you viewed in your computer's RAM (if you have less than a gigabyte of RAM, it stores less).

Caching pages in memory allows faster back-browsing -- meaning better performance as you navigate the web -- but this can be a lot of data and less RAM for other apps to use.

Given the rising popularity of web-based applications which require greater amounts of system resources, could it be that the web is simply getting too heavy for a svelte browser to handle?



But as Chris Pirillo points out, "the issue isn't really about cluttering Firefox with more features that could slow it down and make it more unstable -- the issue is in not fixing outstanding, documented, replicable bugs before adding more features to the core."







But today many things that started out as extensions are now part of the Firefox core feature set and yet many problems remain.










Bruce Perens, a open source advocate and observer, believes that whatever Firefox's problems, the community can repair them.

"If customers want a stripped-down version of Firefox, someone in the open source world will make one that they like."

Pirillo thinks Firefox may not keep up. "Some people love the simplistic nature of Firefox, but I'm one who believes that minimalism is a gigantic weakness."







The advent of more sophisticated web pages and applications has driven the Firefox developers to a major rewrite of Gecko the engine that renders pages in Firefox.

Firefox 3 will use Gecko 1.9 which offers significant performance boosts even in the early alpha builds available today. Firefox 4 is also scheduled to include [Tamarin][1], a new Javascript rendering engine donated to Mozilla by Adobe.

"In general we're psyched about the way people are pushing the limits of the web," Schroepfer says. "And we're excited about incorporating Tamarin into Firefox 4 which should significantly improve Javascript performance."