It works except there is one minor but very annoying problem.

Before I had sound stuttering problem but it was fixed by changing
the SystemResponsiveness to 20 (from 100) on the Registry.

After that I realize that there is another sound stutter problem, but
this time it happen every few seconds, and very short (less than
100 ms I think). I found that RMClock caused this, because when
I open the window it gives me more sound stuttering, even when
I click a button/text-box/etc on its main window. This affect not
just sound but movie and game also affected, in short the entire
system.

I use RMCLock to undervolt my CPU so it would generate less heat /
noise and consume less power. It was fine on XP, I don't know in
Vista tough.

Anyone have tips?

BTW, yes, processor scheduling is optimized for programs in System
Properties.

Sorry for my English...

what happens when you deactivate RMClock?

Its gone. Sorry, I forgot to write this earlier.

Found something! I opened Task Manager and enable
"Show processes from all users" and when try to change
the priority it showed as realtime!

Now, let see what caused this? How can I change the
priority when it started?

EDIT: Found this http://forum.rightmark.org/topic.cgi?id=6:1149
(7th post, from the developer himself)