Thermal Grizzly Liquid Cooling Block Prototype for Reference GeForce RTX 5090 FE Reduces GPU Temperature by 25 Degrees

The head of Thermal Grizzly and part-time authoritative YouTube blogger Roman “Der8auer” Hartung showed a prototype of a custom water block for a liquid cooling system developed for the reference version of the GeForce RTX 5090 Founders Edition video card.

Image source: YouTube / Der8auer

As you know, the reference version of the GeForce RTX 5090 Founders Edition has an unusual design. The card formally consists of three boards: the main board with the GPU, memory chips and power subsystem elements; the PCIe x16 interface board; and the video connector board. Such a complex modular design practically excludes the possibility of using the reference GeForce RTX 5090 Founders Edition for a project to create a custom liquid cooling system circuit.

Der8auer wondered: is it possible at all to develop a custom water block for the GeForce RTX 5090 Founders Edition and does it make any sense at all, given the potential cost of such a solution? As it turned out, it is indeed possible to develop a water block for a video card, but it is very difficult and, most likely, impractical. The project is extremely impractical and at different stages the owner of the video card can expect various problems, including disassembling and assembling the video card. During the experiment, Hartung admitted that several times it seemed to him that he was about to break the video card. For example, to connect the video connector board to the main board of the video card, Nvidia uses a proprietary flat cable, which is attached to the body of the video card cooling system with glue. Damage to this cable will lead to very sad consequences for a video card with a recommended price of $ 2000.

Hartung rated the complexity of the project to equip the GeForce RTX 5090 Founders Edition with a custom water block at 8.5 points out of 10, comparing it with similar experiments to develop water blocks for Nvidia NX 7950 GX2 and NX 9800 GX2 video cards from the distant 2006-2008. These accelerators, we recall, consisted of two printed circuit boards, each of which had one graphics processor installed. Despite this, liquid cooling systems were also developed for such solutions at one time.

Before disassembling the graphics card, Roman conducted some tests for comparison. Disassembling the graphics card and installing the water block took up most of the time allotted for the published video, which shows the complexity of the entire process. Since this is an early prototype of the water block, Thermal Grizzly did not even have time to develop a proprietary back plate for it – its role was played by the standard plate from the Founders Edition. In the process, Hartung also checked the composition of the liquid metal used as a thermal interface in the GeForce RTX 5090 Founders Edition using a spectrometer. It turned out that it contains 10% tin, which makes it very similar to the composition of Thermal Grizzly’s Conductonaut thermal interface. However, Hartung noted that the Conductonaut Extreme version of the liquid metal is more effective than Nvidia’s thermal interface.

Before installing the water block

According to Der8auer, if such a water block does make it to retail, its consumer version will definitely contain less copper to reduce the cost. During the first installation of the water block on a video card, regular thermal paste Kryonaut brand Thermal Grizzly was used instead of liquid metal, and new liquid thermal pads Thermal Putty Pro were used as a thermal interface for memory chips and elements of the VRM power subsystem of the video card.

After installing the water block

The first tests with the water block showed that its use led to a decrease in the temperature of the graphics processor by up to 25 degrees – under load, the chip heated up to only 50 degrees Celsius. The operating temperature of the memory chips decreased by 30 degrees and amounted to only about 60 degrees Celsius. Under load, the GPU with the water block worked at a frequency of about 2680 MHz, which is slightly higher than when using a conventional cooling system.