Mugen 5 if you can't fit the Thermalright Macho / ARO-M14G.
NH-U14S has staggered heatpipes but performance is close enough that you should only buy it if you can get the newer version with AM4 support out of the box.
NH-D15 = 49.5°C
NH-U14S = 50.6°C
Mugen 5 = 53.3°C
CPU-only temp with overclocked Ryzen 7 , 3.9 GHz at 1.475 volts in Prime95:
NH-U14s single fan = 79.9°C
ARO-M14G = 83.3°C
Ryzen 1700X @ 3.9GHz
NH-D15 = 61°C
ARO-M14G = 64°C
Last edited by AlphaC; 06-09-2019 at 04:59 PM.