Hello,
another thought on this subject, it may be totally off but then checking it wouldn't hurt...
is the newer soundcard installed in the last slot of the MoBo, the socalled SLAVE PCI SLOT? if so try it in another slot, some cards (be it gfx, sound, or interface cards (scsi, nic, or IDE)) will not function proberly when installed there or if another card is installed there...
the reason why I mention this, is that it happened to me, installed a SCSI card (conveniently at the last slot) and voila I had chopped sounds from my Soundcard aswell as faulty transfers on the scsi bus! as soon as I switched slots the sound would work fine and the scsi card did aswell...
Ben
PS - One learns thru mistakes, if you don't learn then you haven't made any mistakes?