A method of detecting and preventing over current induced system failure is provided. An OC protect controller monitors a CPU total power consumption based on received CPU activity information. In response to the monitoring, if the CPU power consumption is over a threshold, then the OC protect controller outputs a frequency dithering control signal to reduce the CPU clock frequency such that the CPU does not reach an OC limit. The OC protect controller also outputs a PLL frequency control signal to reduce the PLL clock frequency to improve system efficiency.