With my mac (iMac DV SE Graphite 400mhz 256MB), I can't run iTunes in the background while using other programs. It ALWAYS crashes from lack of memory within half an hour.
If I run it in the foreground, it will run happy, but as soon as I open up a few other programs and try to work in them (BBEdit, IE, MSN, etc) it hangs the WHOLE computer. Total kernel panic.
I did some tests checking RAM usage, and it would continually creep up and I did other things. Must be a memory leak, or what someone said before, a bad carbon port.
iFunk