"With the ten-core / 20-thread Core i9 7900X CPU having a 140 Watt TDP, it's a lot to keep cool with air cooling. Even more, with the soon-to-launch new Core i9 models, you really need a beefy heatsink fan if wishing to avoid water cooling. In this article are some tests with different Noctua heatsinks. Besides being able to cool these 2017X processors, the other requirement too is that they fit within 4U space requirements. The heatsinks benchmarked today included the Noctua NH-C14S, NH-U9S, Noctua NH-D9L, NF-A9 PWM fan, and NF-A14 PWM fan."