you have put a lot of thought into this and so have others but it is my opinion that a 400mhz g4 is barely wuick enough to run osx, let alone, cpu hogging programs like limewire. try to be a freeloader and see if it helps. i have no problems on my g4 867 640mb ram that many other 400 - 600 mhz <500ram users seem to be having all over the postings. you can only adjust your prefs or tweak your computer (which is risky).