PowerTOP - PowerTOP is a Linux tool to diagnose issues with power consumption and power management.
Laptop Mode Tools - Laptop Mode Tools is a package of userspace scripts for Linux kernel "laptop mode".
RMClock - RightMark CPU Clock Utility (RMClock) is a small GUI application designed for real-time CPU...
upower - UPower is an abstraction for enumerating power devices, listening to device events and querying...
CrystalCPUID - CrystalCPUID is a CPU utility software. Key Features: Support AMD64/EM64T
Processor Hardware Control for Linux - Processor Hardware Control is a project to allow CPU voltage/frequency changing from userspace.