Does Firefox 7 solve the memory leak problem?

The beta version of Firefox 7 for Windows and Mac is already out just days after the final release of Firefox 6. Mozilla claim that it features significant memory fixes that go a long way to solving the memory leak problem that is encouraging more and more Firefox users to switch to Chrome.

Firstly, it should be made clear that a memory leak is different to memory usage. A memory leak is when an application suddenly starts guzzling RAM for no apparent reason – as Firefox frequently does. Memory usage is simply the amount of RAM that an application needs to run.

I conducted a short simple experiment on a fresh install of both Firefox 6 and 7 without any add-ons installed. I opened the same 6 tabs in Firefox 6 and Firefox 7 Beta and observed their memory use over a 2 hour period. The results were enouraging. Although Firefox 7 Beta 1 still uses about as much memory as Firefox 6, it does appear to have largely solved the memory leaking problem.

The 6 tabs I opened in each browser were OnSoftware, Softonic, BBC, Microsoft, Apple and YouTube:

The memory use by Firefox 6 after opening them was 131,700K:

Compared to Firefox 7 Beta 1 which was slightly less at 112,768K:

I left them both running idly and checked 1 hour later. This is when the memory leak became apparent. Firefox 6 had shot up almost 100,000K to 220,544K:

Firefox 7 Beta 1 had only increased a little bit however to 130,952K.

Next I closed three of the same tabs and left the browsers running idly for another hout after which I checked memory usage again. Firefox 6 had decreased quite a lot to 148,064 – but that’s still more than Firefox 7 Beta with 6 tabs open.

Firefox 7 Beta had actually increased memory usage for some reason – but only by around 7,000K to 137,440K.

Mozilla claim that Firefox 7 has much improved memory management due to something called Memshrink which can reduce memory usage by up anything up to 50% on previous versions of Firefox. While I wouldn’t say it has improved memory usage by this much, it does seem to have significantly cut down the memory leak.

Other improvements in Firefox 7 include enhancements to Firefox Sync, increased performance for HTML5 Canvas animation and better CSS3 support. The interface is pretty much the same as Firefox 6, with a minimalist toolbar, and they’ve kept the “Feedback” button in the top right corner where you can easily submit thoughts on what you like and don’t like about Firefox 7. Like most Firefox betas however, the major downside is that many plug-ins and add-ons won’t work with it yet.

Download Firefox 6 and Firefox 7 Beta to judge for yourselves whether Mozilla have managed to finally tackle Firefox’s memory leak.

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