Peltier liquid cooling has always been exotic and niche, but only CPU coolers have adopted the technology, leading to the question of whether or not GPUs can benefit from this cooling solution as well. TrashBench on YouTube answered that question in a recent video, putting an RTX 4060 and RTX 3070 to the test using a homemade Peltier liquid cooling system using AIOs, a custom loop, and homemade DC controllers. Sadly, testing revealed that despite having thermoelectric properties, the results were underwhelming.

For the uninitiated, Peltier liquid cooling takes advantage of the thermoelectric effect to achieve sub-ambient temperatures. A semiconducting material is attached to a liquid cooling system and an electric power source. Electricity cools one side of the semiconducting material but generates heat on the other side. In practice, liquid coolers with this tech rely on the semiconducting material to cool the chip, while the liquid cooling portion is largely focused on removing heat from the semiconducting material itself.

TrashBench's homemade Peltier cooling solution was comprised of a complex arrangement of controllers, radiators, tubing, and even AIO liquid coolers. Two Arctic 360mm AIOs were used to cool the Peltier units alone, and two homemade DC controllers were attached to the Peltier units to regulate power. Waterblocks were attached to the other side of the Peltier units to cool the liquid coming from the GPU waterblock. Both Peltier coolers together consumed 360 watts of power.

To start, TrashBench benchmarked an RTX 4060 with the Peltier coolers active to get a baseline, achieving 38 °C on the GPU core, and 24 °C liquid temperature with 23 °C ambient air. With the twin Peltier coolers active, the RTX 4060's GPU temperature dropped by 10 °C to 28 °C, and liquid temperatures dropped by 10 °C as well, down to 14 °C after 20 minutes of load in 3DMark Time Spy. These temperatures were taken after the Peltier coolers were given 20 minutes to cool the loop before activating a GPU stress test.

The YouTuber also ran a "warm start" in which the Peltier coolers were turned off, then back on, to see whether the loop could cool itself back to the same temperatures. Temperatures were slightly warmer with this method, achieving 32 °C on the GPU core and 18 °C liquid temperatures after 20 minutes running 3DMark TimeSpy. Regardless, both tests saw the GPU achieve sub-ambient temperatures.

Next, the YouTuber tested a more power-hungry RTX 3070 to see if his homemade Peltier cooling solution could handle the higher thermal output. Baseline results for the RTX 3070 test saw the GPU reaching 40 °C on the core and 29 °C liquid temperatures. With the Peltier coolers engaged, the RTX 3070's GPU core reached 33 °C and the liquid temperature 21 °C after 20 minutes in 3DMark Time Spy.

TrashBench's testing reveals that Peltier liquid cooling is not worth it, despite its potential to achieve sub-ambient cooling. The YouTuber's testing demonstrates the Achilles heel of Peltier cooling solutions: extreme power inefficiency. To achieve effective cooling, the cooler alone has to consume almost as much power as the chip it is cooling. The cherry on top is that the liquid cooler responsible for cooling the Peltier material has to dissipate that same amount of wattage as well for the system to be effective.

This is why Peltier coolers have not received much attention. The last cooler we reviewed with this technology was the Cooler Master ML360 Sub Zero, which we rated three stars, criticizing its cooling performance and power consumption. The cooler achieved inferior multi-core performance to regular AIOs while consuming nearly 200 watts on its own.

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Aaron Klotz is a contributing writer for Tom’s Hardware, covering news related to computer hardware such as CPUs, and graphics cards.