Firefox 7 to cut down the memory footprint

Firefox 6, which moves to the Beta release channel today, introduced a significantly improved about:memory page with buttons that can manually trigger garbage collection (GC) and cycle collection (CC). Garbage collection frees up memory by clearing old and unused JavaScript objects; cycle collection does the same for DOM objects, including web pages. By hitting these buttons repeatedly — or by hitting “Minimize memory usage”, which triggers both processes three times in a row — you can reduce Firefox 6′s memory footprint significantly.

In Firefox 7, however, which will feature-freeze and percolate down to the Aurora channel today, there are two big changes that should reduce the memory footprint of Firefox for all users: increased GC frequency, and defragmentation of memory chunks used by various core Firefox processes. Increased GC frequency should massively improve the performance of Firefox over long, multi-day browsing sessions, and less fragmentation will result in memory footprints that are tens or hundreds of megabytes smaller than they currently are.