Explained! Mounting Power Supply Up vs Down (PSU)

Power supply unit is an essential component and when building a computer we take care of many aspects but often overlook PSU orientation, today we’re here to help you with should you mount PSU Up or Down.

Power supply unit shortly knows as PSU or SMPS.

Standard PSU have a Fan on one of the side, which flows air inside PSU and eventually throws air from rear vents. Older PSU has a back fan that works as exhaust. The question is how should you put PSU on your cabinet, the options are quite simple.

If PSU is placed Top in Cabinet

Situation 1. The cabinet has vents on top: Mount it Down. This may overheat your PSU, but a good choice to reduce CPU and GPU temperature.

Situation 2. Cabinet has top vents: Mount Fan facing down for exhaust, and Fan Up facing for better intake of PSU. This usually keeps your PSU cool.

If PSU is placed bottom in Cabinet

Decide what you need.

  1. PSU Cool temperature: Mount PSU with Fan facing Downside for better intake, it keeps the power supply cool.
  2. CPU/GPU Temperature: If you mount it Fan Up facing, it’ll work as Exhaust Fan and reduce cabinet temperature.

When your cabinet has top power supply position with a separate chamber.

Cabinet situation – if power supply position is on top, and there is a vent on top of the cabinet case, put it upward facing so it can take air from outside.

On the other hand if there is no top vent on your cabinet, put it downward facing, the fan will get air from inside the cabinet and exhaust it from rear. It will also lead psu to work as an exhaust fan and decrease the temperature.

PSU position cheat sheet.

  • No chamber + Top vents = Upward facing
  • No chamber + No top vents = Downward facing

When your cabinet has bottom power supply position (with a separate chamber).

1. Chamber don’t have top vent – in this case the vent will be on the bottom side to put your PSU, down facing.

2. Chamber have top vent – put PSU upward facing.

3. Bottom position with no chamber, upward facing.

  • Bottom chamber + Top vents = Upward facing.
  • Bottom chamber + bottom vents = Downward facing.
  • No chamber + No vents = Upward facing.
  • No chamber + Bottom vents = Upward facing.

So this was a quick troubleshoot for people building a PC. If it help, do share it with your friends so they know the best way to put PSU. It is nice that you can use a Power supply to work as an additional exhaust fan to keep your system cool.

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