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The bottom shows four feet with rubber padding. The removable dust filter to the left sits under the PSU and can be pulled out to clean.
The H500 has shield plating (white ) that you use to hide the cables in the middle segment. Your PSU is separated in that lower left compartment. Air will be drawn in from the front based fan intakes. Graphics cards can be any size really.
In the front, you could opt to mount LCS with support Up to 280mm.
At the inside top, you can see plenty of clearance/space for cooling. The top side os more limited - with 1 x 120mm (1 Aer F120 Case Version included) / 1 x 140mm.
Space for the PSU?, not an issue.