Modder der8auer builds 110cm 3D-printed chimney to passively cool Ryzen 7 9800X3D without fans, cuts temps by 19C — radically simple PC mod uses the 'stack effect'

der8auer tested 3D-printed chimney extensions to boost natural convection in a water-cooled PC.

As the chimney got taller, airflow through the radiator improved, with the final 110cm setup performing best.

On an AMD Ryzen 7 9800X3D test bench, CPU temperature dropped from a peak of 90°C to 71°C, while water temperature also fell.

The experiment shows that fanless cooling can benefit significantly from stack effect and chimney geometry.