msr-tools 1.3 Read and write Model-Specific Registers (MSR)
The MSR Tools project provides console utilities to directly access the Model-Specific Registers (MSRs) and CPU ID of Intel-compatible processors:
cpuid: show identification and feature information of any CPU
rdmsr: read MSRs from any CPU or all CPUs
wrmsr: write to MSRs on any CPU or all CPUs
These tools can be used to query and modify certain low-level CPU parameters, such as the Turbo Boost ratio and Thermal Design Power (TDP) limits.
MSR addresses differ (greatly) between processors, and any such modification can be dangerous and may void your CPU or system board's warranty.