NVIDIA Jetson Cooling: A Thermal Design Guide for Orin and Thor

Jetson cooling is the thermal path that carries heat from an NVIDIA Jetson module’s processor to the air or structure around the system: a fan, a finned heatsink, a fanless chassis or a heat spreader bolted to an enclosure wall. It decides which power mode the module can hold, and so how much of its rated AI performance you actually get in the field.

NVIDIA Jetson modules have been used in industrial systems since the original Jetson Nano, and today’s Orin Nano, Orin NX, AGX Orin and Thor modules sit in a wide range of carrier boards and box PCs. Orin Nano and Orin NX modules are sold bare, without a fan or heatsink, while AGX Orin and Thor modules carry an integrated thermal transfer plate that still has to be connected to a heatsink or enclosure. Either way, the cooling is part of the system design, not part of the module.

The carrier board shapes the cooling too, because it sets the mounting points and form factor the heatsink or spreader has to fit; how to choose the right Jetson carrier board covers that decision. This guide covers how much heat each module makes, the power modes that control it, the four cooling methods, heat sinks against heat spreaders inside enclosures, and how to check a design before it ships.

Almost all the electrical power a module draws ends up as heat, so the power mode is the heat load the cooling has to remove. The table lists the NVIDIA power ranges; the carrier, NVMe drive, cameras and USB devices add to it at system level.

The Super modes changed the picture for the smaller modules. JetPack 6.2 raised the clocks and memory bandwidth of the Orin Nano and Orin NX, taking an Orin NX 16GB from 100 to 157 TOPS, at the cost of a 40 W top mode. JetPack 7.2 did the same for the AGX Orin 32GB, from 200 to 241 TOPS at up to 60 W. Our answer on Jetson Super mode explains the mechanism, and our Jetson modules comparison sets out the power range of each module next to its performance.

A power mode is an NVIDIA profile that caps the module’s power and sets how many CPU cores run and how fast the CPU, GPU and memory clock. On a running system it is selected with the nvpmodel tool: sudo nvpmodel -q shows the current mode and sudo nvpmodel -m <id> sets another, which persists across reboots. The mode IDs differ by module and JetPack release, so read them from the system rather than assuming them.

A mode is a ceiling, not a guarantee. If the cooling cannot hold the die temperature, the module throttles inside the mode, so a system set to 40 W in an undersized case can deliver less than one set to 25 W that never throttles. Size the mode with the enclosure, not after it.

Jetson modules protect themselves. Sensors on the die feed thermal zones in the operating system, and as the temperature rises the module first reduces clocks, then shuts down. NVIDIA’s thermal design guide for Orin NX and Orin Nano (TDG-11127-001) puts software throttling at about 99 °C and shutdown at 105 °C on the die, and NVIDIA quotes the die sensors to about ±3 °C. The AGX Orin series has its own guide (TDG-10943-001) with limits set at the thermal transfer plate.

Throttling is the quiet failure. A camera system that hits its frame rate on the bench in a cool room can slip in a cabinet in summer, with nothing in the logs except slower inference. Our guide to thermal throttling explains the general mechanism on any processor, and our answer on junction temperature covers the die limit itself.

There are four practical options: the standard Jetson fan, an active heatsink with an integrated fan, a passive heatsink or fanless chassis, and a heat spreader, also called a thermal transfer plate, for conduction cooling. Each suits a different power level and installation.

Each option is chosen for the module’s power draw and the installation’s air flow and environment. Our comparison of active and passive cooling covers the trade-offs on any computer; the sections below cover what is specific to Jetson.

The active Jetson fan in the developer kits attaches to the module using a spring-loaded backing bracket and thermal paste. Because it uses the same onboard power connector, it fits a wide range of carrier boards, and alternative off-the-shelf fans for a given carrier usually differ only slightly.

For rugged use, the heatsink or heat spreader is best mounted directly to the Jetson carrier board, which gives structural support and load relief to the module inside an enclosure. These assemblies should use thermal gap pads to carry heat from every hot component, which matters most when the module runs at its top mode.

Active heatsinks suit higher thermal loads and compact systems, such as AGX Orin modules running up to 75 W or an Orin NX in its 40 W Super mode. The fan speed is controlled by the module: from JetPack 5 the nvfancontrol service ramps the fan as the temperature rises, using thresholds and profiles set in its configuration file. That keeps the fan slow when it is not needed, which reduces noise, power and wear.

A passive heatsink uses natural convection to remove heat without fans. Typically made from aluminium, it uses fins to increase the surface area that transfers heat to the surrounding air. This fanless design is the standard for most industrial Jetson PCs: with no moving parts, there is less dust build-up and no fan to fail, which suits dusty or remote sites.

The trade is derating. A fanless chassis sheds heat in proportion to the difference between its fins and the air around them, so its rating falls as the ambient rises and as the power mode goes up. Many fanless Jetson computers are offered with an optional fan kit for the top mode. Our answer on the advantages of fanless computers sets out why industrial buyers still prefer them where the mode allows.

A Jetson heat spreader, or thermal transfer plate, spreads heat from the module across a larger surface and conducts it into an adjoining structure, such as a cabinet wall, a mounting plate or a vehicle chassis. Typically made from aluminium for its thermal conductivity, it moves heat out of the enclosure rather than into the air inside it, which avoids heat build-up and the need for fans.

With no moving parts, heat spreaders also suit shock and vibration. The plate stays securely mounted and keeps consistent thermal contact, which makes it a good fit for vehicles and heavy machinery subjected to constant motion and impacts.

The low-profile design suits confined, sealed and waterproof enclosures, where keeping an unbroken barrier is crucial. With no vents or openings, a heat spreader helps keep out dust, debris and water, which makes it a common choice for outdoor edge AI, such as smart city and roadside equipment.

Jetson box PCs are also available with integrated flat-top heat spreaders instead of finned heatsinks. Designed for installation inside industrial cabinets, they give a compact, low-profile system that sheds heat through the cabinet structure. Our explainer on conduction cooling covers the principle, and our answer on how heat pipes work explains the pipes inside many Jetson heatsinks and plates.

Which is better for a Jetson computer inside an industrial cabinet or outdoor enclosure: a heat sink or a heat spreader? A heat sink needs enough surrounding air, or air flow, to remove heat. If a Jetson system with an active or passive heat sink is placed inside a compact enclosure, the heat from every component raises the air temperature inside the cabinet, which can recreate the thermal problem the heat sink was meant to solve.

Conduction cooling is the alternative: a heat spreader carries heat from the module to the outside of the chassis or enclosure. Good mechanical design and material choice are what make it work. If the enclosure is large enough and heat build-up is not a concern, a passively cooled heat sink can make installing the system in the cabinet simpler.

Inside a sealed cabinet, also count the cabinet itself: solar gain, other equipment and the outside temperature set the air the computer sees. Our guide to electrical enclosure cooling works through cabinet heat loads, and with many Jetson systems deployed outdoors, our separate guide to designing outdoor computer enclosures applies to both box PC and carrier board builds. Our answer on what a heat sink is covers the basics.

Manufacturers rate a Jetson computer’s operating temperature for particular power modes and cooling options, and the figures show how much the mode costs in ambient headroom. These are taken from the product pages in our range.

Worked example. An Orin NX 16GB camera system has to run in a roadside cabinet that reaches 45 °C inside on a summer afternoon. At 25 W, a fanless computer rated to 55 °C has 10 °C of margin. In the 40 W Super mode the same computer is rated to 35 °C, below the cabinet temperature, so it would throttle. The choices are to stay at 25 W, add the fan kit and an air path, or move to a heat spreader that dumps the heat into the cabinet wall. The model’s frame rate at 25 W decides which is right.

Cold matters as well. Commercial Orin modules are specified down to about −25 °C, while the AGX Orin Industrial module runs from −40 °C; our answer on the industrial temperature range explains what such ratings cover.

A thermal design is only proven under the real workload at the hottest ambient the system will see. A few tools on the Jetson itself make that straightforward.

NVIDIA’s Jetson Power Estimator helps size a custom mode before hardware exists, but NVIDIA notes its estimates can differ from measured power, so treat it as a starting point. When the result is marginal, the cheapest fixes are usually a lower power mode, a better thermal interface or a heat spreader path, before a larger module or a fan. Our explainer on TDP explains how power ratings relate to cooling on x86 processors, which helps when a project compares the two.

The Diamond Systems JACKSON-ER shows the choice at board level: the JAXER-ASY-ONX16 is built either with a heat spreader that mounts the assembly upside down to an enclosure wall or with a heat sink and 5 V fan. We fit the cooling option, set the power mode the enclosure can hold and test each Jetson system under load before it ships.