Apparently Firefox uses 1MB chunks to keep long living system objects alive. The memory bloat some users were reporting was significant, including one instance where there was a 80 per cent drop in Firefox memory commitment using increased frequency of garbage collection.
Given Mozilla's rapid release schedule, the changes are not expected to be incorporated into Firefox until Firefox 7, as Firefox 6 is nearing its entry into the beta channel, though judging by the results, Mozilla would do well to get it included as soon as possible.
