The be quiet! Dark Base Pro 901 is the objective winner of this comparison, securing victories in six out of eight evaluated categories. Its most significant technical advantage is the inclusion of 2.5" drive bays, which offer a 150% increase in capacity compared to the alternative. This superior storage flexibility establishes the be quiet! Dark Base Pro 901 as the more robust option for users requiring extensive hardware expansion within their system build.

Users who prioritize maximum storage capacity and a feature-rich chassis should select the be quiet! Dark Base Pro 901 for their workstation or high-capacity build. Conversely, the Phanteks G400A is the logical choice for budget-conscious builders, as it holds a 72% advantage in MSRP. Those who do not require the additional drive bays and prefer a more cost-effective solution will find the Phanteks G400A to be the more suitable component for their specific financial requirements.