Just got a new PC...using quad core on XP (enterprise will not upgrade to Windows 7), and notice a performance issue frequently (with music on, it is particularly evident as it becomes a staccato sound). My older PC booted slowly but never had this issue once it was up.
I know...stinks that my company has not yet certified their software to run on Windows 7. Anyways...I have to apologize. I checked the event log (should've checked that FIRST), and noticed frequent disk errors. So, until I get a new disk, I cannot blame anything else.