Pumpless 240mm AiO cooler is only 8C behind traditional pump-powered rival in tests

Professional YouTuber and well-respected hardware enthusiast Roman 'Der8auer' Hartung got his hands on a promising prototype CPU cooler that uses thermosyphon technology. A thermosyphon is a method of passive heat exchange based on natural convection, which circulates a fluid without needing a mechanical pump. Wieland, a German-based company with expertise in copper and copper alloy-made cooling products for CPUs, GPUs, and memory, made this quieter alternative to a traditional AiO liquid CPU cooler. Taking the mechanical pump out of the equation lowers operating noise - but cooling performance is reduced somewhat.

At first glance, the prototype Wieland Cold Plate Gaming product looks like it comes with a typical 240mm radiator with two 120mm fans. Things start to appear a little different on closer inspection, as there is a cylindrical housing on either side with tubing connecting to the CPU block. Due to the lack of a pump, the cooling block is not so chunky, and the good thing is that it means there is no pump to generate noise. 

The unit De8auer has is a prototype unit. That means the design, color, tubing, and other aspects of the design are not finalized. However, we are getting to see a company a typical PC enthusiast may have never heard of - but has years of expertise. It isn't known what kind of fluid is used inside this closed-loop cooling device. The prototype's aluminum block is milled to be compatible with both AMD's and Intel's contemporary sockets.

Der8auer set up his test system in a Dark Base Pro 901 with an AMD Ryzen 9 7950X CPU running at stock settings on an Asus ROG X670E Hero. Since he was unable to get a factory-supplied 240mm AIO, he taped off one of the 120mm fan mounts on his 360mm Corsair H150i AIO for comparison. With both CPU coolers, he used Kryonaut Extreme thermal compound.

With the Corsair cooler, the system monitor indicated the CPU reached up to 95 degrees Celsius on load when running Cinebench R23 with fans set at 1,600 RPM. Der8auer would subsequently fix the Wieland cooler's fans at this speed for an even comparison

Unlike a typical radiator, the Wieland model needs more space on either (short) side due to cylindrical appendages. The initial observation using the prototype was that the idle temperatures were no different than the typical AIO's equivalent. When gaming benchmarks were run, the cylindrical housing on the right was warmer than the one on the left. With the help of a thermal camera, it can be seen that the CPU block maintains a surface temperature of 54.4 degrees Celsius. You can see in the thermal camera image that both the cylinders are running warmer than the rest of the radiator, with the tube coming from the left side being cooler than the one on the right.

Based on the Cinebench R23 stress test, the AMD Ryzen 9 7950X draws 180 - 185W using the Wieland prototype, but with the Corsair AiO the CPU draws 205W. There's only a little over a 1% performance difference in the Corsair cooled system's favor, which isn't significant.  

Promising prototype just 8 degrees Celsius behind its pump-powered Corsair rival

There's always room for improvement. Der8auer noticed that the prototype has a large gap between the fan mount and the radiator allowing the fan's air to escape easily. Perhaps some minor design tuning to reduce this gap could pay performance dividends. Der8auer also suggested working on adding more copper to the CPU cooling block. Further research and engineering efforts could bring extra incremental benefits.

As things stand, the CPU cooled by the Wieland AiO operates at about 8 degrees Celsius higher peak temperatures than when using the traditional Corsair AiO. However, the relatively quiet Wieland might be preferred by some, like professionals working in game development and post-production tasks, or those regularly editing music and movies. Another potential benefit of not having a pump is that there is one fewer mechanical component to fail.

It's safe to say that Wieland's liquid cooling looks very promising even in the prototype stage. We also ponder whether the lack of a pump could result in reduced costs, but until products like this are manufactured at scale by multiple companies we would feel foolish to expect such a design to undercut a traditional AiO.

Other companies have tried making thermosyphon technology CPU coolers. Raijintek had a concept six years ago. Der8auer also made a similar cooler which he showcased a few years ago but couldn't be sold as the fluid used was banned by the EU a year after the prototype was made. 

As of now, Wieland's Cold Plate Gaming solution seems to be on the right track. Despite needing certain improvements typical of prototypes, it looks promising as a soundless, virtually maintenance-free cooler that could match traditional AIO cooling with enough refinement.