i7z

Start i7z (needs to be run in superuser mode)

$ sudo i7z

sudo i7z [options]

-h, --help
    Displays the help message and exits.

-V, --version
    Shows version information and exits.

-T, --temperature
    Displays only the current CPU package temperature.

-C, --cstates
    Displays only the current C-state residency information.

-P, --pstates
    Displays only the current P-state frequencies and Turbo Boost status.

-w <delay>, --wait <delay>
    Sets the update delay in seconds (default is 1 second).

-o <file>, --output <file>
    Redirects output to the specified file.

-L, --log
    Logs raw data in a machine-readable format to the output file.

-u, --update-once
    Updates once and exits without entering interactive mode.

-A, --auto-detect
    Attempts to auto-detect C-state ranges for older CPUs.

-p, --plain
    Outputs data to stdout without using the ncurses interactive display.

-s, --package-only
    Shows only package-level C-state residency, not per-core.

-r, --reset-cstates
    Resets C-state counters (requires --update-once).

-F, --full-freq
    Displays individual frequencies for all cores.

i7z is a powerful command-line utility designed to provide real-time monitoring of Intel Core i3, i5, i7, and Xeon CPUs. It offers deep insights into your processor's operation by displaying crucial metrics such as core frequencies, actual and nominal speeds, package and individual core temperatures, and detailed C-state (idle power states) residency percentages. It also shows P-state (performance states) activation and whether Turbo Boost is active.

By reading Model Specific Registers (MSRs) directly, i7z gives users a granular view of how their CPU behaves under various loads and idle conditions. This makes it an invaluable tool for performance tuning, power consumption analysis, diagnosing thermal throttling, or simply understanding your CPU's dynamic behavior.

i7z requires root privileges (or the CAP_SYS_RAWIO capability) to access the CPU's Model Specific Registers (MSRs). Ensure the msr kernel module is loaded (e.g., sudo modprobe msr).

It is designed specifically for Intel Core series (i3/i5/i7) and some Xeon processors and will not work on AMD CPUs or older Intel architectures. Compatibility can vary with different kernel versions and hardware configurations. For scripting purposes, use options like -u or -p to get non-interactive output.

To function correctly, i7z relies on the msr kernel module (which provides access to CPU MSRs) and the ncurses library for its interactive terminal interface. Ensure these are available on your system.

The output of i7z typically shows:
Core Frequencies: Actual clock speed and nominal speed of each core.
Temperatures: CPU package temperature and individual core temperatures.
C-States (C0-C10): Percentage of time the CPU spends in various idle power-saving states. C0 is the active state; higher C-states (e.g., C3, C6, C7, C8, C9, C10) represent deeper sleep states with increased power savings.
P-States: Current performance state, often indicating the CPU frequency multiplier and whether Turbo Boost is active.
BCLK: Base Clock frequency of the CPU, which affects the final core frequency.

i7z was primarily developed by Roman Mamedov to monitor the behavior of Intel's then-new Core i-series processors, specifically focusing on observing C-state transitions and Turbo Boost functionality. It emerged as a specialized tool when general monitoring utilities didn't offer such granular, low-level CPU insights. Its development helped users understand how modern Intel CPUs manage power and performance dynamically, and it has been maintained to support newer architectures.

s-tui(1), sensors(1), turbostat(8), cpupower(1), htop(1)