Itunes Visualizer, does visualiser respond a noisy system? Options

[Jaysee]

Hi, just a thought....When playing CDs or MP3s etc in itunes with the visiualizer on when I first got my G5, I used to get almost no visuals when music had stopped, just the odd straggler trail now and then against a black background. Now my machine is over a year old I've noticed its still tripping away visually when the music stops, picking up on little 'dr who' type visual feedback tracers and iterating away like crazy. It's obviously responding to *something* going on, does anyone think it betrays a noisy component of my sytem? I'm puzzled. It doesnt worry me particulariy...but maybe it would be a good test of something either mechanical or electrical showing signs of ageing??
cheers, jc