Under the Advanced tab, there is a section called AMD CBS head over there and change the following settings. Core Performance Boost should be left off since you want to manually enter the Core Ratio and not boost at all. And Global C-state Control will cause instability if it is left one since it will attempt to lower voltages when the CPU is idle.
- Core Performance Boost: Set to Disable.
- Global C-State Control: Set to Disable.