Ibook (dual Usb) 600mhz Macosx Only Runs At 400 Mhz



MacOSX(10.3.9) as well as MacOSX Tiger on my IBook (Dual USB) G3/600 Mhz started to run the processor only at low performance (400 Mhz). Energy behavior is set to maximum processor power.

Only MacOS 9.2.2 runs at normal speed (600 Mhz). Here I can switch between 600 Mhz and 400 Mhz and back again to 600 Mhz.

I tried resetting PRAM as well as NVRAM. The terminal command "sysctl -a" says my processeor´s upper and lower speed limit is 400Mhz.

I cannot remember when this problem started to occur.

I would appreciate if anyone could help.