64bit, realtek HD audio
driver / network card guy here.
Just been suffering from the same sound stuttering / crackling problem.
And I think I just fixed it by disabling my wireless card! I think I only noticed a crackle once since then, whereas before it was so frequent I could not even bear to listen to any mp3. If I notice anything again I will try disabling my keyboard hotkey monitor.
Previously I tried changing audio and network
drivers, to no avail.
So it seems it is a CPU latency problem, and people are fixing it by several different methods.
Summary: I think I just fixed my audio stuttering problem by disabling my wireless network device!