Cooling hot Ryzen 3700x with Noctua l9a-AM


Minimal Tinkerer
Original poster
Aug 3, 2019
I have just finished my build, with a Dan A4 v4 case and Asus Rog Strix X470-i mobo, but I'm currently testing temperatures with open case.
I ran a benchmark on Linux and the temperature reached quickly 80-81c, in a couple of minutes with the fan spinning at almost 2500rpm.
Is this expected? Or perhaps I did not apply thermal paste the best way? Please share your experience if you have a similar setup and any hint.
I am planning to downvolt a bit, but would like to get the best possible temps with a default config first.


Aug 16, 2017
There's a few similar fellows and infos here.

Basically, because it's a binned cpu, they easily boosts/reach their PPT all the time. Which is 88W for 65W TDP AMD cpus.

Saying so, 80 isn't too bad, really. Maybe test with prime95 to see if it throttles?

If you want lower temps you'd need a bigger cooler than NH-L9a-am4.
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Innovation through Miniaturization
Feb 1, 2016
Depending on how lucky you are with your Silicon you should be able to undervolt by 75-100 milivolts with no loss of performance. This will lower power draw by 10-15 Watts (15-20%) which will reduce the amount of heat output somewhat proportionately. Really good post on the subject here:



Minimal Tinkerer
Original poster
Aug 3, 2019
Thank you very much. Yeah sure as soon as I'm finished improving the wiring will try will prime95 with closed case and 3d-printed fan duct, and post results here.

Still wondering if a repaste could improve things however.


(no relation)
Jul 11, 2019
It's expected. Tested both open air and closed case with plenty of airflow (SM580 with 4x 140mm Noctua fans). Tamed mine (only truly overheating during AVX torture test) by undervolting, which I like to do for better efficiency and less heat in the system, anyway. The L9 just isn't a big enough heatsink to keep the 3700X very cool at stock voltages, though it would be ideal for 3600X.
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