other way around. the new computer/sound card is producing 1/3 # of decodes as the old computer/sound card.

Hank,

A Joe says (And he should know!) any soundcard will work unless it is actually faulty.
An expensive one is not required, WSJT is only using a very small audio range.
Expensive ones are useful for Audiophiles or maybe soundcard SDRs where low noise and the full range is required.
How well does your new soundcard work when playing music fed from the mic socket without overloading it?

73 Alan G4ZFQ

If a different sound card doubled your number of decodes, there was something very wrong with the previous sound card or the way you were using it.  Nearly all sound cards made in the past 10 years or more should produce very close to identical decoding results.
  -- 73, Joe, K1JT