German overclocking specialist Der8auer has showcased a custom water block for NVIDIA's flagship RTX 5090 Founders Edition, achieving a remarkable 30-degree Celsius reduction in core GPU temperatures. The prototype copper cooling solution demonstrated peak operating temperatures of just 43.8°C, compared to the stock cooler's 73.8°C under identical testing conditions. The design features an all-copper construction with a substantial 14 mm-thick cold plate, engineered specifically for optimal thermal transfer from the GB202 die. While maintaining the dual-slot form factor of the original Founders Edition cooler, the water block incorporates multiple cooling channels beneath a transparent top panel that reveals the coolant flow.

Memory temperatures also significantly improved, dropping by 38 degrees Celsius below stock measurements. Despite its impressive thermal performance, the prototype faces several engineering challenges. The team was constrained by the graphics card's display output ribbon cable, which prevented a more compact design closer to the actual PCB dimensions. Additionally, the Founders Edition card's unique split PCIe finger design presented structural concerns that require additional reinforcement before any potential commercial release. Der8auer's prototype prioritizes function over aesthetics, omitting common features like RGB lighting in favor of raw cooling performance. The water block's industrial design reflects its proof-of-concept nature, though the transparent top panel offers practical utility for monitoring coolant flow. While no retail release timeline has been announced, Der8auer indicated that addressing the PCIe slot structural support issue remains a critical milestone before any commercial version could be considered.