Billet Labs has built a water-cooled gaming PC with three stacked radiators operating without radiator fans. Its reported tests showed the GeForce RTX 5080 avoiding thermal throttling during gaming, while the CPU throttled in some workloads and coolant temperatures reached around 60°C or higher during combined stress testing.
The London-based cooling firm lists an AMD Ryzen 7 9800X3D processor, Nvidia GeForce RTX 5080, 32GB of memory and 2TB of storage. The reported configuration also includes a B850 Aorus Pro motherboard.
A radiator stack designed for natural convection
The build places three differently sized radiators above the heat-generating components. Billet Labs describes the arrangement as relying on natural convection: warm air rises through the stack, encouraging cooler air to enter from below. Copper plumbing connects the cooling components, with the hardware mounted on an aluminum platform.
Although the radiators operate without fans, the liquid loop still uses a powered pump. The project’s aim of reducing mechanical noise also required adjustments elsewhere: Felix, a Billet Labs founder, reportedly disabled the motherboard fan and set the pump to 80% speed during testing.
The project follows the company’s wall-mounted Walley system and Victorian cast-iron radiator PC, Raddy. Raddy still used fans, and Felix described pump cavitation that required regular radiator flushing. The new build reuses core performance components from that system.
Reported temperatures rose under heavier loads
The project’s reported testing covered idle operation, Peggle, Cinebench and more demanding games, including Halo 3, Expedition 33 and Cyberpunk 2077.
In the gaming tests, Billet Labs reportedly observed no GPU thermal throttling. The CPU reached about 95°C or higher and throttled slightly in some scenarios.
Running Cinebench and FurMark simultaneously produced the heaviest combined workload described in the project account. Reported power draw exceeded 450W, coolant temperatures reached around 60°C or higher, and the CPU throttled again.
The power-supply fan also reportedly became audible during that combined test. The absence of radiator fans therefore did not mean the entire system remained fanless under every tested condition.
These figures are reported results from Billet Labs’ custom configuration, rather than independently reproduced benchmarks.
Felix suggested mounting a single 120mm fan above the radiator stack to pull air upward and improve cooling. In the account accompanying the original report, that improvement was an expectation rather than a demonstrated result.
