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Power Modes

Tune the power consumption and performance of your ZED Box Mini
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The NVIDIA® Jetson™ module of the ZED Box Mini and of the Mini Carrier Board supports several power modes. Each power mode caps the number of online CPU cores, the number of active GPU TPCs, and the maximum frequencies of the CPU, GPU, DLA, and memory (EMC) to keep the module within a given power budget.

Choosing the right power mode lets you trade performance against power consumption and heat, which is especially important for battery-powered systems.

Power supply of the ZED Box Mini

The ZED Box Mini is powered through its power input connector, with the provided power supply or a regulated input:

Power sourcePower input
Terminal block connector10.5V to 13.5V (12V nominal), up to 60W

This is enough for all the supported power modes of your module. For sustained workloads in the highest power modes, install the fan for ZED Box Mini, as described in Cooling.

If your system is battery-powered, the power supply must deliver the peak power of the selected mode. Sudden voltage drops trigger hardware throttling of the CPU and GPU clocks.

Supported power modes

The tables below list the power modes supported by the ZED Box Mini for each Jetson module, with their nvpmodel ID and main clock limits.

ModeIDOnline CPU coresCPU max (MHz)GPU max (MHz)Memory max (MHz)
10W061510.4624.752133
7W_AI14806.44082133
7W_CPU249603062133

MAXN is an unconstrained mode, available on the Orin NX modules, that enables the maximum number of cores and the maximum clock frequencies. It has no fixed power budget: hardware throttling is engaged when the module power exceeds its limit, so MAXN does not always give the best performance, and NVIDIA does not recommend running heavy workloads in this mode for prolonged periods.

If the system becomes unstable in MAXN mode, install the fan for ZED Box Mini, or select a mode with a fixed power budget.

  • Always check the modes defined on your device, as described in Check the current power mode, before switching.
  • A higher power budget does not always mean a faster GPU. For example, on the Orin NX, the 20W and 25W modes enable more CPU cores but cap the GPU at a lower frequency than the 15W mode. Benchmark your own application in each candidate mode to find the one that suits it best.

The complete clock configuration of each mode, including DLA, PVA, and SoC engine frequencies, is available in the NVIDIA Jetson Linux Developer Guide.

Check the current power mode

Display the active power mode:

sudo nvpmodel -q

The command prints the name and the ID of the mode. For example, on an Orin NX 8GB in MAXN mode:

NV Power Mode: MAXN
0

List all the power modes defined on your device, with their IDs and names, and the default mode applied after flashing:

grep "^< POWER_MODEL\|^< PM_CONFIG" /etc/nvpmodel.conf

For example, on an Orin NX 8GB:

< POWER_MODEL ID=0 NAME=MAXN >
< POWER_MODEL ID=1 NAME=10W >
< POWER_MODEL ID=2 NAME=15W >
< POWER_MODEL ID=3 NAME=20W >
< PM_CONFIG DEFAULT=2 >

On the Ubuntu desktop, the current power mode is also displayed next to the NVIDIA icon in the top bar.

Change the power mode

From the command line

Select a power mode by its ID:

sudo nvpmodel -m <mode_id>

For example, to select the 20W mode of an Orin NX 8GB, which has ID 3:

sudo nvpmodel -m 3

The selected power mode persists across reboots until you change it again.

Some mode changes modify the number of active GPU TPCs, which can only be applied at boot. In this case, nvpmodel asks for a reboot:

NVPM WARN: Golden image context is already created
NVPM WARN: Reboot required for changing to this power mode: 0
NVPM WARN: DO YOU WANT TO REBOOT NOW? enter YES/yes to confirm:

Type yes to reboot immediately. The new mode is applied after the reboot.

From the Ubuntu desktop

  1. Click the NVIDIA icon in the top bar. The current power mode is displayed next to it.

  2. Open the Power mode submenu and click the mode you want to set.

    Power mode menu of the nvpmodel GUI

    Power mode menu on a ZED Box Mini Orin NX 8GB. The modes listed depend on your Jetson module.

  3. If the new mode requires a reboot, a dialog asks for confirmation. Click OK to reboot and apply the new mode.

    Reboot confirmation dialog

Maximize the clocks with jetson_clocks

By default, the CPU, GPU, and memory frequencies scale dynamically with the load (DVFS), up to the limits of the active power mode. The jetson_clocks script locks these clocks at the maximum frequencies of the current power mode. This reduces latency and gives more stable performance, for example during benchmarks, at the cost of a higher idle power consumption.

jetson_clocks never exceeds the limits of the power mode: select the power mode first, then run jetson_clocks.

CommandDescription
sudo jetson_clocks --showDisplay the current clock settings
sudo jetson_clocks --storeSave the current clock settings to ~/.jetsonclocks_conf.txt
sudo jetson_clocksLock the clocks at their maximum frequency for the current power mode
sudo jetson_clocks --restoreRestore the clock settings saved with --store

To return to dynamic frequency scaling later, store the settings before maximizing the clocks:

sudo jetson_clocks --store
sudo jetson_clocks
# ... run your workload ...
sudo jetson_clocks --restore
  • The effect of jetson_clocks does not persist across reboots.
  • After running jetson_clocks, you cannot change the power mode with nvpmodel anymore. Reboot the device first.

Create a custom power mode

If none of the predefined modes suits your application, you can define a custom power mode, for example to keep more CPU cores online at a lower frequency, or to cap the GPU frequency.

  1. Use the NVIDIA Jetson Power Estimator to estimate the power consumption of your configuration and to generate the corresponding nvpmodel configuration.

  2. Back up the current configuration file:

    sudo cp /etc/nvpmodel.conf /etc/nvpmodel.conf.bak

    /etc/nvpmodel.conf is a link to the configuration file of your module, for example /etc/nvpmodel/nvpmodel_p3767_0001.conf for the Orin NX 8GB.

  3. Edit /etc/nvpmodel.conf and add a new < POWER_MODEL ID=<id> NAME=<name> > block. The easiest way is to copy the block of the closest existing mode, then:

    • give it a unique ID and a descriptive NAME,
    • enable or disable CPU cores with the CPU_ONLINE CORE_<n> 1|0 lines,
    • adjust the MIN_FREQ and MAX_FREQ values. CPU frequencies are expressed in kHz; GPU, memory (EMC), DLA, and PVA frequencies in Hz. A value of -1 means no limit.

    For reference, this is the 15W mode of an Orin NX 8GB, with 4 CPU cores online, the CPU capped at 1420.8 MHz, and the GPU capped at 612 MHz:

    < POWER_MODEL ID=2 NAME=15W >
    CPU_ONLINE CORE_0 1
    CPU_ONLINE CORE_1 1
    CPU_ONLINE CORE_2 1
    CPU_ONLINE CORE_3 1
    CPU_ONLINE CORE_4 0
    CPU_ONLINE CORE_5 0
    FBP_POWER_GATING FBP_PG_MASK 2
    TPC_POWER_GATING TPC_PG_MASK 252
    GPU_POWER_CONTROL_ENABLE GPU_PWR_CNTL_EN on
    CPU_A78_0 MIN_FREQ 729600
    CPU_A78_0 MAX_FREQ 1420800
    GPU MIN_FREQ 0
    GPU MAX_FREQ 612000000
    GPU_POWER_CONTROL_DISABLE GPU_PWR_CNTL_DIS auto
    EMC MAX_FREQ -1
    DLA0_CORE MAX_FREQ 614400000
    DLA1_CORE MAX_FREQ 614400000
    DLA0_FALCON MAX_FREQ 294400000
    DLA1_FALCON MAX_FREQ 294400000
    PVA0_VPS MAX_FREQ 115000000
    PVA0_AXI MAX_FREQ 115000000

  4. Select the new mode:

    sudo nvpmodel -m <id>
  • Keep the total consumption within the limit of your power supply.
  • Capping the memory (EMC) frequency below the bandwidth required by your application can cause functional failures, for example dropped camera frames.

Monitor power consumption and temperature

Monitor the system while your application runs to validate your power mode choice.

tegrastats

tegrastats is installed with JetPack. It reports the CPU and GPU load and frequencies, the memory usage, the temperatures, and the power consumption of the module rails:

sudo tegrastats --interval 1000

tegrastats output

To log the statistics in the background, for example during a long test:

sudo tegrastats --interval 1000 --logfile ~/tegrastats.log &

Stop the background logging with sudo tegrastats --stop.

You can also start tegrastats from the Ubuntu desktop: click the NVIDIA icon in the top bar, then Run tegrastats.

Jetson Power GUI

The Jetson Power GUI is installed with JetPack. It displays the CPU, GPU, and memory frequencies and loads, the readings of the temperature sensors, and the instantaneous and average power of each monitored rail.

To start it, click the NVIDIA icon in the top bar, then Run Jetson Power GUI.

Jetson Power GUI main tab

The fan values reported by the Jetson Power GUI and by jtop do not reflect a fan connected to the 12V fan connector, whose speed is not controlled by software (see Cooling).

The Thermal / Power Monitor tab shows the throttling and shutdown limits of each temperature sensor, and the voltage, current, and power of each monitored rail:

Jetson Power GUI Thermal / Power Monitor tab

The Record section at the bottom of the Main tab captures a log over a given duration, and plot graph… plots the recorded or real-time data. This helps you compare the power consumption of your application in different power modes.

jtop

jtop, from the community jetson-stats package, is an interactive terminal monitor that also lets you change the power mode and toggle jetson_clocks:

sudo apt update
sudo apt install python3-pip
sudo pip3 install -U jetson-stats
sudo jtop --install-service

The last command installs and starts the jtop service, and adds your user to the jtop group. Log out and log in again, or reboot, then run:

jtop

jtop main screen

Throttling

The temperature of the Jetson module depends on the power mode, the workload, the cooling, and the ambient temperature. The operating temperature range of the ZED Box Mini is -20 °C to +50 °C (-4 °F to 122 °F).

When a temperature sensor of the Jetson module reaches 99 °C, the software starts throttling the clocks. At 103 °C, hardware throttling is engaged, and the system shuts down at 104.5 °C to protect itself. The clocks are also throttled when the input voltage drops or when the module power exceeds its electrical limits.

On the Ubuntu desktop, the NVIDIA icon in the top bar displays a notification when the system is throttled because of an over-current event or a high temperature.

If you observe throttling or unstable frame rates during long runs, install a fan, select a lower power mode, or reduce the workload of your application.

Cooling

The ZED Box Mini provides a 12V fan connector for active cooling. The fan for ZED Box Mini is recommended for high power modes, including MAXN, and for high ambient temperatures.

The fan connector has two pins, power and ground, with no PWM or tachometer signal. The fan speed is therefore not controlled by software: the jetson_clocks --fan option and the nvfancontrol fan profiles have no effect on a fan connected to it.

Further reading