The Western Digital WD Black SN8100 4TB is the objective winner, securing victories in five out of seven comparable specifications. Its most significant advantage is a sequential write speed that is 112% better than the alternative. This performance lead makes it the superior choice for users prioritizing high-capacity storage and rapid data writing capabilities over other considerations.

Choose the Western Digital WD Black SN8100 4TB if you require maximum storage space and the fastest write performance for demanding workloads. Conversely, select the Western Digital WD Black SN850X 2TB if your primary goal is to minimize your initial investment, as it holds a 75% advantage in MSRP. This smaller drive is the logical option for budget-conscious users who do not require the higher capacity or the increased write speeds of the larger model.