Here again!
I have started with MacOS and used a program to see the cpu temp.

CPU A reach 80C from time to time but CPU B dont pass from 60 C. Perhaps I have bad sensors but what is the normal temperature?
Why in morphos 3.4 temp grow to more than 100 with full fan velocity? One of friend of mine can't test MOS cos his G5 is at full fan speed all time but with MacOS is warm.
His mac shows 50 C in macos but 80 in MOS. What is happening?

Can I disable CPU A?
Can I buy to CPU 2.0 GHz and replace my current 2.5 ones simply changing them?