Noctua’s new NH-L9A-AM4 low-profile heatsink was built specifically for AMD’s AM4 socket and will cool up to a 65W CPU or APU. This diminutive little cooler has just a 114 x 92mm footprint and stands at only 37mm tall with the included Noctua NF-A9x14 PWM fan. That 92mm fan has a max speed of 2500 rpm, yet generates only 23.6db.

Opening this package up reveals the classic Noctua unboxing experience. The presentation makes an already nice product feel that much more premium. In the box we’ve got the backplate with four mounting screws, longer screws for the fan, should you want to replace it with something thicker, a fan voltage reducer for even quieter operation, and a syringe of NT-H1 thermal compound.

Installation of the Noctua NH-L9A-AM4 does require access to the back of the motherboard, as the backplate screws into the heatsink from behind. Keep that in mind if you’re purchasing this as an upgrade, as you may need to remove your motherboard to install this cooler.

I tested the Noctua NH-L9A-AM4 against the stock AMD Wraith Stealth on a new Ryzen 5 2400G APU. The test was conducted in a small form factor case at both stock speeds of 3.5GHz, and at 3.95GHz @1.3875v, a pretty hefty overclock for this chip.

The results were interesting with both coolers performing roughly the same at stock speeds. This makes sense, as both the Wraith Stealth and the Noctua L9a are rated for up to 65W TDP. Both idled at 31C, and were split by a single degree under full synthetic load. The NoctuaNH-L9A-AM4 temped in at 72C, with the Wraith at 73C. One major difference between the two coolers was the noise level. The Wraith, while not loud, was beginning to border on being unpleasant in my office.

Jumping up to that 3.95GHz mark, the Noctua starts to really differentiate itself from AMD’s stock offering. The Wraith Stealth idle increased to 38C, and jumped up to 84C under full synthetic load, with the fan ramping up to 100% at times. The Noctua didn’t seem phased at all by the increased current, seeing just a 3C increase at Idle, and MATCHING its temperature under load. All while staying at the same whisper-quiet 23dB.

So what do I think of the Noctua NH-L9A-AM4? While I don’t think it makes sense for every situation over the fairly impressive Wraith Stealth, do keep in mind, inside this case we’re dealing with pretty low airflow, and both coolers kept the APU well under its thermal ceiling of 105C. But for small form factor builds, or just to cut down on the noise of your PC, I would say the Noctua NH-L9A-AM4 is well worth the $40 asking price.



