Noctua NH-L9a-AM4: A Very Low-Profile AMD Ryzen Cooler
At just 37mm tall, the Noctua NH-L9a-AM4 is one of the shortest yet quite capable CPU heatsink fans we have seen yet for AMD Ryzen processors.
When looking for a heatsink with a small stature for an AMD APU mini PC build for HTPC / file storage use-cases (more on that build in the next day or two), the Noctua NH-L9a-AM4 fit the criteria and so I went with that given the success with the many Noctua heatsinks we have used over the years. For those potentially interested in the NH-L9a-AM4 for an AMD APU like the new Ryzen 5 3400G or for lower-end Ryzen CPUs, I ran some benchmarks with this cooler.
The NH-L9a-AM4 is just 37mm tall with the 92mm fan installed while being 114mm wide and 92mm deep while weighing less than a half kilo. This Noctua AM4 heatsink is constructed with a copper base and heatpipes, aluminum fins, and soldered joints with nickel plating. This heatsink is equipped with the Noctua NF-A9x14 PWM fan that spins at 600~2500RPM with a noise level between 14.8 dBA and 23.6 dBA.
This Austrian-engineered low-profile heatsink is designed for AMD AM4 APUs/CPUs up to 95 Watts. Noctua backs this heatsink with a six-year warranty.
I've been using the Noctua NH-L9a-AM4 with a Ryzen 5 3400G and it's worked out quite well. I ran some thermal tests compared to AMD's reference cooler for the Ryzen 5 3400G, the Wraith Spire. Tests of the Noctua cooler were done in the default PWM mode (as was the case with the Wraith Spire) and again when just running the fan at full-speed. Even when the Noctua fan was running at full-speed, it was very quiet.
Installation was easy and straight-forward though may be an inconvenience for some as installing/removing the heatsink does require access to the rear of the motherboard PCB for screwing the heatsink from the back-plate.