Hi Blindjim - I use a reclocker, the Empirical Audio Pace Car 2 (with Audiocom's Superclock 4), in my computer based setup. The addition of the reclocker to my system resulted in greater perceived resolution, better imaging focus, less shrillness in the high frequencies, and a lower noise floor. I wrote a review of the Pace Car 2 if you would like to know more about my experiences with it.
Suffice to say, it made me a true believer in the importance of reducing jitter for getting the most from computer based audio. Whether the results of lowering jitter would be more beneficial than the other changes you mentioned, I cannot say. Good luck.
Suffice to say, it made me a true believer in the importance of reducing jitter for getting the most from computer based audio. Whether the results of lowering jitter would be more beneficial than the other changes you mentioned, I cannot say. Good luck.