The Western Digital WD Black SN850X 4TB is the objective winner, securing victories in five out of six measured categories. Its most significant technical advantage is a sequential read speed that is 1204% better than the alternative. This massive performance lead establishes it as the superior choice for users prioritizing high-speed data access and large-capacity storage solutions. The Western Digital WD Blue SA510 1TB only outperforms its counterpart in one category, specifically offering an MSRP that is 86% better.

Choose the Western Digital WD Black SN850X 4TB if you require top-tier sequential read performance and maximum storage density for demanding workloads. Conversely, the Western Digital WD Blue SA510 1TB is the appropriate selection for budget-conscious buyers who prioritize a lower MSRP over the high-speed capabilities and larger capacity offered by the more powerful drive. Your decision should depend on whether you value raw speed and space or a more accessible entry price.