This behavior can be caused by many things. To narrow down the possibilities, here are some questions:
1) Does the problem always occur at the same point in a song? If you re-play the song right away, does it still exhibit this problem at the same point?
2) If you copy the song onto your local HD and play it from there, does the problem go away?
3) Do you have any network activity enabled (including filesharing) that may be competing with iTunes for resources? If so, try disabling them and see if the problem goes away. [i know you said that you disabled extensions, but I don't know which ones, specifically.]
4) If you change the disk cache settings in your control panel, does that change the problem? There may be unwanted interactions between the accelerator card's cache and the OS's cache.
5) And along similar lines...What about virtual memory? If you've enabled it, try disabling it and see if the problem disappears.
1) Does the problem always occur at the same point in a song? If you re-play the song right away, does it still exhibit this problem at the same point?
2) If you copy the song onto your local HD and play it from there, does the problem go away?
3) Do you have any network activity enabled (including filesharing) that may be competing with iTunes for resources? If so, try disabling them and see if the problem goes away. [i know you said that you disabled extensions, but I don't know which ones, specifically.]
4) If you change the disk cache settings in your control panel, does that change the problem? There may be unwanted interactions between the accelerator card's cache and the OS's cache.
5) And along similar lines...What about virtual memory? If you've enabled it, try disabling it and see if the problem disappears.