Use the STICK timers only when absolutely necessary, i.e. if a machine
consists of CPUs running at different speeds, for driving hardclock as
these timers in turn are driven at frequencies as low as 5MHz, resulting
in bad granularity compared to the TICK timers. However, don't employ
the workaround for the BlackBird erratum #1 when using the TICK timer
on machines with cheetah-class CPUs for performance reasons.

Reported by: Florian Smeets