@v13: I think we are talking about little different heap memory fragmentation problems and effects here. I am mainly concerned (in this Java vs C++ issue) the increased pagefaults due to increasing heap memory fragmentation in long living OOP programs like www-browser. The problem with fragmentation is that locality of the objects is getting worse.

I do see Firefox still taking too much available RAM when it is runnign long time, but that is not why I restart it every few days, because the machine do not start swapping yet. But firefox seem to get slow, and restarting it makes a real difference. I notice this also if I disable flash. Javascript engine in Firefox has pretty good GC nowadays, so I don't think that is a problem but C++ memory management itself.