Comment 29 for bug 229745

there have been more and more improvements on this in firefox 3.5 and firefox 3.6 (trunk), to say that this is fixed as good as possible. Some fixes might not land in xulrunner 1.9, but we will have 1.9.1 soon enough. in anycase, if you still have an issue in jaunty you could also test ext4 filesystem which should help to make the filesystem access done by firefox less IO hungry.