The Western Digital WD Black SN8100 4TB is the objective winner of this comparison, securing more individual specification victories than its competitor. While the SK Hynix Platinum P51 2TB holds a significant 53% advantage in MSRP, the Western Digital WD Black SN8100 4TB provides the most impactful benefit with a 100% increase in storage capacity. This makes the latter the superior choice for users prioritizing maximum space over initial cost.

Choose the Western Digital WD Black SN8100 4TB if your primary requirement is high-capacity storage for large libraries or extensive data sets. Conversely, opt for the SK Hynix Platinum P51 2TB if you are working within a stricter budget, as it offers a substantial advantage in MSRP. Selecting between these two drives depends entirely on whether your build demands the doubled capacity of the Western Digital option or the cost efficiency of the SK Hynix model.