AdBlock does use a lot of memory, but it never seems to free that memory either. You can load up 100 web pages, then close them all and memory is still eaten. In the past I've sat and watched the browser idle with resource monitoring tools and watched it leak memory over time with AdBlock's memory use going up even though no new web pages were being accessed. So I've directly witnessed it memory leaking before.

Other extensions leak memory also and I've got another one doing so right now which I believe is "RequestPolicy Continued" which is flagged experimental. Browser's been OOM'ing ever since I installed that one, often within an hour of starting the browser. ;/

I discovered that Mozilla plans to launch official 64bit support for Firefox for Windows in the next release and that beta builds are available right now (41 beta 7 currently), so I've upgraded to the 64bit beta browser. There are some caveats which others need to consider before switching to the 64bit browser which I'll leave to people's Google skills to figure out for themselves, but none of the issues were a concern to me. So far the only one problem I've encountered is that Firefox 41 will refuse to allow unsigned extensions to run by default with no way to disable it, so 5 of my extensions including one critical one failed to load due to not being signed. Contrary to Mozilla's own documentation mentioning there is no setting in about:config to disable this in the stable nor beta version of the browser, and that it can only be disabled in the developer and nightly builds - the option to disable it DOES exist in the beta and it does work. After restarting 3 of the previously unsigned extensions got magically updated anyway, and the one that I need that got blocked is now working so hopefully they fix it properly on their end for the official release of Firefox 41 on Sept 22.

Surprisingly, I've had no other issues with the beta so far although I did anticipate more issues. I should state that my browser while loaded down heavily with extensions - is completely pluginless. No Flash, no Java, no Quicktime or any other 3rd party plugins whatsoever. People who are using any of those or Silverlight or other addons may want to do their research before considering the 64bit browser as the plugins may be disabled by default or otherwise incompatible, or may need some googling around to figure out how to get them to work. Shouldn't be an issue for any co-propellerheads. :)

The upside of Firefox 64bit at least, is that with 32GB of memory, shitty browser extensions that leak memory can now leak 29GB more RAM before the browser crashes, and long before that happens the system will start to become sluggish or behave oddly and draw attention to investigate and discover the problem and solve it on my own best time/conditions than a random poorly timed nosedive. :)

YaY! 32GB memoryleak padding! :)

Firefox 41 beta downloads for all supported platforms (32 & 64 bit) quick link:

<span class="bold">https://www.mozilla.org/en-US/firefox/beta/all/</span>