Intake air must make a sharp 90 degree turn when entering the case with the front door closed. This will result in more air turbulence and lower efficiency when compared to a traditional front vent design.
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The top-mounted vent allows dust particles to settle inside the case. It also redirects exhaust noise out the top of the PC.
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Note the positioning of the rectangular VIDEO air INTAKE duct (middle right of the back panel). This duct is positioned between the top hexagonal exhaust vent for the PC and the bottom rectangular exhaust vent for the power supply. Hot rising exhaust air is re-directed back into the case via the video air intake duct!
I prefer to apply Dynamat or equivalent to the side panels. This is a cheaper and more effective solution to the noise problem.
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We see the power supply cage at the bottom left of these pictures. An extra long power supply will come very close to the 120 mm case fan located midway in the bottom chamber, resulting in excessive air turbulence.
A modern power supply has one large bottom-mounted cooling fan. There appears to be 3/4 inch of free space between this fan and the bottom of the Antec can. Incoming air must pass through this 3/4 high opening and make a sharp 90 degree turn before reaching the fan. The results...more noise and less efficient cooling.
Some modular power supplies DO NOT have a rear vent. The entire back plate of the power supply is used to populate the output connectors. Let's also not forget the PATA and SATA cables extending from the hard drives. These wires will negatively impact airflow across the bottom chamber. In this case, the exhaust air must go around the power supply before it can exit the case.
If we remove the 120 mm case fan as suggested by this article, then the heat from the four front hard drives would have to go through the power supply before exiting the case. This will result in a very HIGH temperature at the power supply. Remember that in a traditional ATX case, the 100W of heat from the CPU is dissipated 360 degree into the motherboard (cooling fan blowing into the CPU). The rear 120 mm case fan AND the power supply share the duty of heat extraction. Very few power supplies will run at 80% efficiency. 75% is a more realistic number.
Let's take a look at the other extreme, with only one hard drive. The case fans in the top chamber would have to work harder to cool the system because they are NOT getting the extra help from the power supply.
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You pay big bucks for a case only to find that you should use SATA hard drives to provide adequate cooling to the power supply! I also don't like to mount the hard drive vertically, as this will place an uneven load on the main drive bearing assembly.
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