I have already answered this question several times
Graal doesn't use 100% CPU time. It uses the
application idle timer to do precise timing. It is the only
way in windows to do precise timing, all other games use
that too. Windows is also using this thing to 'detect'
how much time a process takes on the CPU, like you
can see it is not precise because it doesn't do it
like some real OS do.
Some games disable the precise timing when they are
not activated, then you don't see 100% when you
are switching to the task manager.