Mozilla sweats the fat from Firefox 7

Noticeable memory improvements in Windows.

Mozilla on Tuesday delivered Firefox 7 for Windows, Mac and Linux, which addresses its reputation as a memory hog and adopts the hidden "http:" prefix that Chrome introduced. 

Firefox 7, under the right circumstances, could use up to 50 percent less memory than its predecessor, which should mean a “snappier” browsing experience and fewer pauses, Mozilla's Hacks blog reported. 

The lower memory usage would mostly be noticeable on Windows systems, when many tabs in Firefox were open at once or when a user kept them open for long periods. 

Other conditions that would bring out the improvements included when running other programs that used lots of memory.  

In reality, due to different browsing behaviour, there could be a wide variance in memory consumption. 

Firefox users would “often” see 20 to 30 percent less memory being used and “sometimes” see a 50 percent reduction.

Mozilla has grappled, with varying degrees of success over Firefox’s lifetime, to deal with memory usage, according to Melbourne-based Mozilla programmer, Nicholas Nethercote, who recently ran extensive testing on the latest browser.  

“Firefox 2 was quite bad, but Firefox 3, 3.5 and 3.6 were substantially better. But Firefox 4 regressed again, partly due to a large number of new features,” he noted in a recent blog, adding that improvements in Firefox 7 were “significant”.

The new browser also addressed several security issues, and offered a new opt-in system to collect telemetry data from users.

Mozilla is set to release two more updates before the end of 2011, with Firefox 8 due 8 November and Firefox 9 by 20 December.