The Western Digital WD Black SN850X 1TB wins in 4 out of 7 comparable specs, with 1 tie. Its biggest advantage is Sequential Read (109% better).
970 EVO Plus 2TB wins in 2 specs (Capacity: 100% better).
Recommendation
Choose WD Black SN850X 1TB if you want the best overall performance — especially sequential read.
Choose 970 EVO Plus 2TB if capacity matters more to you.
