i recently started converting a large amount of music from mp3 to aac format and importing into itunes. my computer, for the first three days was completely functional. now, as the fourth day is ending (its about halfway done converting and importing) it's become, for lack of a better word, slow as molasses in a freezer. it takes about 5-10 minutes for applications to open. itunes is still going at the exact same speed (5-6x), but it doesn't let any other application use more than 1% of the CPU. so i was wondering if there's any way to make itunes use only say 90% of the CPU and let all the other applications use the remaining 10%. basically what was happening before was that the system would take focus away from itunes when i switched the application, itunes would go slower, and the other application would go faster. now it doesn't take the focus off of itunes, so it's trying to make itunes go as fast as possible, and run everything else with maybe 2% of the CPU. the computer is an 800 Mhz G4 imac running 10.3.5 and the latest version of itunes. any help on the matter would be appreciated 
