You reset PRAM and NVRAM for setup default the sensors
turn off mac g5
turn ON mac g5
before you see gray screen down
holddown COMAND + OPTION + P + R
mac g5 is startup
and you wait ear 2 sounds of startup
now holdoff key COMAND + OPTION +P +R
the g5 setup now on default
when start up
go system preference
go energy saver
go nergysaver/option
go velocity of procesor and setup slow
with this your g5 work silence and fine