For one time use I would say Artic Silver 5 but takes about 200 heating cycles to cure. Thats about 1~1.5 months where its not as effective. Artic MX-4 is great right off the bat but depending on how hot your CPU gets it may need reapplied about once every several years. It has a durability of 8 years but think that is normal use temps wise. Cant go wrong with either. Given you can keep a max 4.1Ghz Ryzen cool with a Noctua U12S I would say your going to be running cool.