The Corsair 6500X is the objective winner of this comparison, securing more category victories across the evaluated specifications. Its most significant advantage is the storage capacity, as the Corsair 6500X offers 50% more 2.5" drive bays than the alternative. This makes it the superior choice for users who prioritize internal storage expansion and hardware configuration flexibility over other cooling or layout considerations.

Choose the Corsair 6500X if your build requires extensive 2.5" drive support for high-capacity storage needs. Conversely, select the Phanteks G400A if you prioritize out-of-the-box cooling performance, as the Phanteks G400A provides a 100% advantage in the number of included fans. The Phanteks G400A is the better option for users looking to minimize additional component purchases by utilizing a case that comes fully equipped with pre-installed cooling hardware.