Direct IHS Cooling Pushes Threadripper 9995WX to New Limits

Daily Technology

09/02/2026

Cooling high-performance workstation processors presents a significant engineering challenge. As core counts and power consumption increase, conventional thermal solutions can become a bottleneck. A recent project involving AMD's 96-core Ryzen Threadripper PRO 9995WX CPU demonstrates a novel approach that redefines the boundaries of processor cooling by integrating the water block directly into the CPU's own hardware.

A New Cooling Paradigm

Standard liquid cooling involves multiple layers for heat transfer: from the CPU die to the integrated heat spreader (IHS), and then through a thermal interface material to a separate water block. Each layer introduces thermal resistance. The experimental method undertaken by the tech channel Geekerwan eliminates these intermediate steps. By precisely machining water-cooling channels directly into the CPU's IHS, the heat spreader itself becomes the cold plate. This allows coolant to flow just millimeters above the processor's core chiplet dies (CCDs), creating a far more efficient thermal pathway compared to conventional high-end water blocks.

Engineering an Extreme Solution

The development process was iterative, beginning with tests on older Threadripper CPUs to validate the concept. The final design for the 9995WX features a sophisticated S-shaped channel layout, optimized through simulation to maximize surface area and ensure even coolant flow over the distributed CCDs. The system is powered by an industrial chiller and two 50W Bosch water pumps, highlighting the extreme nature of the build required to handle the thermal load.

Performance Metrics and Results

The effectiveness of this direct-IHS cooling is demonstrated through concrete performance data. With this custom solution, the 96-core CPU achieved a stable all-core overclock of 5.325 GHz. During demanding benchmark runs like Cinebench 2024 and 2026, the CPU package power draw was measured at approximately 1,340W, with the total system pulling around 1.7 kW from the wall. Despite this immense power consumption, core temperatures remained remarkably low, holding steady in the 30°C to 50°C range. The processor achieved benchmark scores exceeding 205,000 in Cinebench R23, 10,080 in Cinebench 2024, and 41,478 in Cinebench 2026. These results showcase a level of thermal control that is unattainable with traditional cooling methods under similar loads, establishing a new benchmark for what is possible in extreme thermal management.

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