Hello FwF,
I have found that these memory problems are resolved when you
stealth browse from a memory stick. I have on my flash drive PortableFirefox (latest updates) with the following extensions NoScript, AdBlockPlus, SiteAdvisor, DrWeb anti-virus link checker, Adblock G updater, NukeAnything, Show IP & PwsHash installed, swift as it can be, no crashes, no crap on the host comp, no traces, no cookies, no history dat, no trace of a browser. Ideal when you do not want to leave a trace, but also for stability.
PocketFlock same story, alas no ported SiteAdvisor plug-in.
I write this posting from inside FF 1.501 en-US. NoScript memory hog, no no sweat whatsoever on a USB stick. For me and other forum folks, go alternate via the mem stick. No traces on the host computer, unless you are not going to them files there (pics etc, first take the also onto the mem-stick).
Safe, clean and fast,
polonus
PS Stealth browsing I learned from bob3160, the man with many a good idea.