well I know for a fact that there are issues regarding performance with Protools w/audiomediaIII and the Amd/via solution.
If you record using an athlon chances are that you will have substandarned performance, including glicthes and other anomalies in your audio tracks.
it has something to do with Via bus holding up the interrupts far too long.
however, there are many who are getting good results with protools using Athlon based solutions but these are very few ppl mostly they are just recording and sequencing loops(short repetative sounds)
as for cakewalk and cubase they seem stable under the Amd domain.
try Protools free version, see if you can actually run it.
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