both units are good so either of them is OK for you .. 600W sounds beefy but the real icing on cake about S12II 520w it has 5 years warranty compared to 3 years on Eco
means i can use tagan psu which i gave the link
or i should buy corsair cx600v2
r u sure seasonic 620 will take all load after ocingyou better get Seasonic S12II 520W reatilg around ~4.25k or better the 620w paying 1k more.