The Thermalright Assassin X 120 Refined SE wins in 2 out of 3 comparable specs. Its biggest advantage is MSRP (72% better).
NH-L12S wins in 1 spec (Noise Level: 4% better).
Recommendation
Choose Assassin X 120 Refined SE if you want the best overall performance — especially msrp.
Choose NH-L12S if noise level matters more to you.
