The Phanteks G400A is the objective winner of this comparison, securing a lead in six out of eight measured specifications. The most impactful advantage provided by this case is its included fan configuration, which offers a 100% improvement over the NZXT H6 Flow. By providing double the cooling hardware out of the box, the Phanteks G400A establishes a clear technical superiority in base component utility compared to the alternative.

Users who prioritize out-of-the-box cooling performance and value the inclusion of pre-installed hardware should select the Phanteks G400A. This option is better suited for builders looking to minimize additional purchases for their thermal setup. Conversely, the NZXT H6 Flow remains an alternative for those who do not require the specific fan advantage offered by the Phanteks G400A, though it does not outperform the latter in any of the measured technical categories.