– A passive, multi-heat-sink loop can cool a high-end CPU/GPU without a fan, relying on natural convective circulation driven by temperature differences.
– The system maintains usable performance even under load, though CPU and GPU temps can exceed typically recommended long-term operating levels (e.g., CPU ~90°C, coolant ~55°C).
– System uses substantial passive hardware (large heat sinks, aluminum plate with thermal pads) and conventional components (Gigabyte Aorus Pro B850, 32 GB RAM, 2 TB SSD, 600W PSU) without modifying the fans on the rest of the case.
Fans are often an annoying part of a gaming PC due to the noise they make, but can hardly be avoided with powerful and correspondingly energy-hungry hardware. Billet Labs, a British manufacturer of high-quality components for PC water cooling systems, shows a modding project in the video embedded below, in which an AMD Ryzen 7 9800X3D and an Nvidia GeForce RTX 5080 ($1,299 on Amazon) are cooled entirely without a fan.
Cooling Concept and Setup
The project uses three heat sinks, which are connected to each other by a passive water cooling system. The heat sinks measure 40 x 20 cm, 28 x 14 cm and 24 x 12 cm. Without a pump, the cooling liquid only circulates due to the temperature differences between the liquid that has direct contact with the CPU or GPU, and the liquid in the heat sinks. This setup aims to passively transfer heat through conduction and convection aided by the natural buoyancy of the warm liquid.
Hardware Configuration
Billet Labs uses a Gigabyte Aorus Pro B850 mainboard, 32 GB RAM, a 2 TB SSD and a 600 watt power supply unit for this PC, which is not modified and is therefore cooled with a fan. The mainboard is mounted on an 8 millimeter thick aluminum plate with thick thermal pads to help distribute the heat. The choice of components is framed as a balance between performance and minimal active cooling, leveraging passive flow dynamics instead of fans.
Performance Observations
Even without a fan, the PC works surprisingly well in many scenarios. In idle, the coolant remains relatively cool with a temperature of 28 °C. If the processor is fully utilized using Cinebench, the coolant heats up to 39 °C after half an hour and the CPU even reaches 90 °C, but performance does not drop. If the GPU is also used, for example in Cyberpunk 2077, the coolant reaches temperatures of over 55 °C – the performance remains stable, but the temperatures are higher than recommended for long-term operation.















