i7z

Start i7z (needs to be run in superuser mode)

$ sudo i7z

i7z [options]

-d
    Daemon mode. Runs in the background, printing data every 5 seconds. Requires redirecting standard output.

-q
    Quiet mode. Suppresses some output.

-c
    CPU number to monitor. Default is all.

-t
    Show package temperature instead of core temperature.

-h
    Show help message.

The i7z command is a command-line utility for Linux systems that provides real-time monitoring of Intel Core i3, i5, i7, and Xeon processor frequencies and temperatures. It's primarily used to check if the CPU is running at its advertised speed, whether turbo boost is active, and to monitor thermal behavior.

i7z polls the CPU's Model Specific Registers (MSRs) to extract data about the CPU's clock speed, multiplier, and temperature. The command displays the core frequency for each individual core, the bus frequency, and the temperature of each core. It also presents information related to turbo boost status, throttling events, and power consumption.

This tool is useful for troubleshooting performance issues, verifying proper CPU configuration after overclocking, and ensuring the CPU is not overheating under load. Note that due to its method of polling MSRs, i7z requires root privileges to function correctly.

Requires root privileges to access MSRs. May not function correctly on non-Intel CPUs or older Intel CPUs. The accuracy of temperature readings depends on the accuracy of the CPU's thermal sensors. The frequency readings are based on instantaneous measurements, which can fluctuate rapidly.

Core Frequency: Shows the actual clock speed of each core in MHz.
Bus Frequency: Indicates the base clock speed of the system bus.
Temperature: Displays the temperature of each core in degrees Celsius.
Turbo Boost: Shows whether turbo boost is active and the maximum turbo frequency.
Throttling: Indicates if the CPU is throttling due to overheating. If throttling, the CPU will reduce its frequency to cool down.

The i7z command was created to provide a more detailed and accurate view of Intel CPU frequencies and temperatures than available through standard system tools. It evolved to fill the gap in monitoring capabilities, specifically targeting the increasingly complex behavior of modern Intel processors with features like turbo boost and variable clock speeds. It quickly gained popularity among system administrators and enthusiasts who needed to verify CPU performance and thermal characteristics. The tool has seen updates to support new Intel CPU generations.

cpufrequtils(1), sensors(1)