X-HD or X-symphony with apogee ad16x
 

hi all,
currently i am using pt 9 with a digi 002 and rosetta 800 on a mac book pro. i want to upgrade to mac pro, apogee ad16x and rosetta 800. i do not get the difference between the X-HD and X-symphony cards. can anybody explain this to me? what do i need to get this thing going?!
thanks,
jan