Power Modes

The NVIDIA® Jetson™ module of the ZED Box Orin 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. This is important on the ZED Box Orin, which uses a passively cooled enclosure with no fan.

Power supply of the ZED Box Orin

The ZED Box Orin can be powered in two ways:

With the DC barrel jack, you can use all the supported power modes of your module.

Supported power modes

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

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 16GB 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 16GB:

< POWER_MODEL ID=0 NAME=MAXN >
< POWER_MODEL ID=1 NAME=10W >
< POWER_MODEL ID=2 NAME=15W >
< POWER_MODEL ID=3 NAME=25W >
< 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 25W mode of an Orin NX 16GB, 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 on a ZED Box Orin NX 16GB. 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.

   

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.

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

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_0000.conf for the Orin NX 16GB.

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 16GB, 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
   CPU_ONLINE CORE_6 0
   CPU_ONLINE CORE_7 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 115000000
   DLA0_FALCON MAX_FREQ 294400000
   DLA1_FALCON MAX_FREQ 115000000
   PVA0_VPS MAX_FREQ 115000000
   PVA0_AXI MAX_FREQ 115000000

4. Select the new mode:

   sudo nvpmodel -m <id>

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

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.

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.

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:

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

Throttling

The ZED Box Orin has no fan, so its temperature depends on the power mode, the workload, and the ambient temperature. Its operating temperature range is 0 °C to 50 °C (32 °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, select a lower power mode, improve the airflow around the ZED Box Orin, or reduce the workload of your application. With PoE+, also check that your setup stays within the 25.5W budget.

Further reading

• NVIDIA Jetson Linux Developer Guide: Platform Power and Performance
• NVIDIA Technical Blog: Power Optimization with NVIDIA Jetson