Mmm... What speakers are you using? I had almost the same problem with a intel bayfield MB(Granted 3 years ago), my logitechs kept making these ticking sounds, but only with them, other speakers didn't do it... Switched the sound card to a SB Audigy, never had that problem again.
Have you tried other speakers yet?
And have you checked your ground wire? Sometimes high pitch whines could be caused by a bad ground connection somewhere.