Intel Undervolt: CPU Tuning Utility

Welcome to the documentation for intel-undervolt, a powerful command-line tool for undervolting and altering thermal/power limits on Intel CPUs. This tool is designed for advanced users who want to fine-tune their processor's performance and thermal characteristics.

It is primarily intended for Haswell and newer generation Intel CPUs.

What Problem Does It Solve?

Modern CPUs often operate under thermal and power constraints. By carefully adjusting voltage and power limits, you can achieve several goals:

  • Reduce heat output: Lowering the voltage (undervolting) reduces power consumption, leading to lower temperatures.
  • Improve battery life: Less power consumption directly translates to longer battery life on laptops.
  • Increase performance: By managing thermal headroom more effectively, you can potentially sustain higher turbo boost frequencies for longer durations.
  • Customize performance profiles: The tool allows for dynamic switching of performance hints based on system load, enabling you to prioritize raw power or energy efficiency as needed.

Key Features

  • CPU Voltage Control: Apply negative voltage offsets to multiple CPU domains, including Core, Cache, GPU, System Agent, and Analog I/O.
  • Power Limit Alteration: Modify short-term (PL2) and long-term (PL1) power limits and their respective time windows for the CPU package.
  • Temperature Offset (TjOffset): Adjust the critical temperature at which the CPU begins to throttle.
  • Hardware P-State (HWP) Control: Dynamically switch the Energy vs. Performance Preference hint based on CPU load or power consumption.
  • Real-time Monitoring: A measure mode to monitor power consumption, core temperatures, and CPU frequencies in real-time.
  • Daemon Mode: Run as a background service to periodically re-apply settings and enable dynamic HWP switching.
  • System Integration: Supports integration with systemd, OpenRC, and elogind for automatic application of settings.

Disclaimer

Warning: This tool may damage your hardware. It directly manipulates low-level CPU settings using reverse-engineered Model-Specific Registers (MSRs). Incorrect settings can lead to system instability, data loss, or permanent hardware damage. Use this tool entirely at your own risk.

Getting Started

Ready to dive in? Follow these steps:

  1. Installation: Build the tool and install it on your system.
  2. Quick Start Guide: Follow a simple tutorial to apply your first undervolt.
  3. Configuration: Learn about all the available settings in the configuration file.