When off-the-shelf cooling can't tame the world's best CPUs, you have to start thinking outside of the box. Chinese YouTube channel Geekerwan has puthe Ryzen Threadripper Pro 9995WX, a 96-core Zen 5 behemoth that costs almost $12,000, to its limits with an eye-opening DIY cooling solution. It features a custom CNC-machined integrated heat spreader (IHS), automotive-grade cooling components, an industrial chiller, and a 37-gallon water tank.
IHS modifications aren't new in hardware circles. We've previously seen the transformation implemented on processors such as the Core i9-14900KS. However, the Ryzen Threadripper Pro 9995WX is a different beast in every sense of the word. The Zen 5 flagship workstation processor isn't just substantially larger than a typical consumer chip; it also features a more complex AMD chiplet design and requires additional engineering effort.
Behind every successful project lies countless hours of preparation. In Geekerwan's case, it took extensive trial-and-error and thermal simulations to arrive at the perfect direct-die IHS design for the Ryzen Threadripper Pro 9995WX. Rather than risking delidding a $12,000 processor, Geekerwan reached out to Tony Yu, General Manager of Asus China, to borrow an IHS for study. The channel purchased several old Ryzen Threadripper 1900X processors and sacrificed them to test various microchannel patterns to identify the most efficient design.
The first challenge was to determine the optimal microchannel depth. Because the Ryzen Threadripper Pro 9995WX's IHS is 0.6mm thicker than the Ryzen Threadripper 1900X, the microchannels must be slightly deeper. Geekerwan used a precision 0.3mm CNC cutter to carve ultra-thin 0.15mm cooling fins with 0.3mm of spacing. The result is a high-density design that maximizes heat transfer.
The team tested 1.5mm, 2.0mm, and 2.5mm cuts on the Ryzen Threadripper 1900X IHS, achieving 82.1, 81.2, and 80.4 degrees Celsius, respectively. The logic is that deeper cuts improve cooling performance, but overdoing it will compromise the IHS's structural integrity and increase the risk of deformation under water pressure. Therefore, Geekerwan settled on a depth of 2.0mm to preserve at least 2.1mm of the heat spreader for safety margins.
对10万元的CPU动刀！水直接流进CPU的终极散热！ - YouTube Watch On
The next challenge was to select a microchannel pattern. Straight microchannels are the industry standard, but Geekerwan's computer simulations showed a better design. Since the author planned to use industrial components for the cooling solution, the liquid velocity and pressure would logically exceed those of normal liquid coolers. By adopting wavy S-shaped microchannels, the heat dissipation area can increase significantly by up to 20%.
Testing on the Ryzen Threadripper 1900X showed up to a 1.2 degrees Celsius improvement between the traditional straight and wavy microchannels. Getting the design from concept to reality was grueling. It took 19 hours of CNC machining inside the Taikan T-700S and the destruction of 14 fragile 0.3mm cutting tools to get the Ryzen Threadripper Pro 9995WX ready. The final result was a beautiful array of one hundred fins of varying lengths on the $12,000 processor's IHS.
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The water block also required careful analysis. The Ryzen Threadripper 1900X and Ryzen Threadripper Pro 9995WX don't share the same design. The two CCDs in the Ryzen Threadripper Pro 9995WX sit at the chip's far edges, unlike the CCDs in the Ryzen Threadripper 1900X that cluster in the center. Due to the chiplet design and the die placement, Geekerwan needed to rethink the water block's design.
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