Question: what is cpu io voltage?
Answer: VCC/VCCIO/CPUIO: Vcc is the voltage at the IO (Input/Output) terminals to the CPU. Generally at 4GHz or under this doesn't need to be adjusted, but at 4.5GHz it can require a small bump to between 1.15V and 1.2V, depending on the quality of your CPU. ... It's default voltage is under 1V.