PSU mounting

t0m3k51

Member
Dec 17, 2010
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I just got a new Antec Three Hundred Two case that has the mounting of the PSU on the bottom.

Do I install the PSU with the fan up or down?
 

lehtv

Elite Member
Dec 8, 2010
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Down.

- the PSU's cables will be closer to the motherboard tray making them a bit easier to route
- no chance of accidentally dropping something into the PSU through the fan grille
- the separation of PSU airflow from case airflow means three things:
a) the PSU will be taking in cool air from under the case instead of warm air from inside the case, potentially lengthening its life span
b) you won't be pulling warm air in different directions which theoretically is good for avoiding potential hot spots
c) 302 is designed for negative air pressure, and this means the case will get dusty over time - but since the PSU is taking air in through a filter, it avoids building up dust (as long as you clean the filter regularly)
 
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lehtv

Elite Member
Dec 8, 2010
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It's possible to avoid dust buildup without cleaning with compressed air more than once a year or even less often. You just need dust filters on all intake areas, regular cleaning of those filters (vacuuming does the job), and positive air pressure (intake CFM more than exhaust CFM) so that dust isn't taken in through unfiltered openings. Blocking any fan slots on top of the case also helps - this avoids dust falling in when the PC is turned off.
 
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Ketchup

Elite Member
Sep 1, 2002
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Just to add a confirmation, lehtv is exactly right. Mounting the fan down will keep air in your case going the right direction.

I love the way the newer quality cases are designed, in that the filters ensure all air entering the case is filtered, so all you have to do is remove any dust that builds up from the OUTSIDE of the case and clean out the filters. You should see less dust inside the case than in older builds, very cool.
 

kleinkinstein

Senior member
Aug 16, 2012
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This is all rather silly, it truly doesn't matter. There have been a few studies done on the benefit of either direction and it showed little or no difference between the two.
 

Ketchup

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Sep 1, 2002
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On my last build I tested both ways and the temps were better with the fan facing down.
 

Face2Face

Diamond Member
Jun 6, 2001
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I have mine facing up right now in my case purley for aesthetics. When I have some time I can run some tests and see if it makes a difference in temps. We all used to have our PSU's sucking hot air from the enitre case when everything was mounted up top. I still have PSU's that are running fine from those days.
 

Ketchup

Elite Member
Sep 1, 2002
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I have mine facing up right now in my case purley for aesthetics. When I have some time I can run some tests and see if it makes a difference. We all used to have our PSU's sucking hot air from the enitre case when everything was mounted up top. I still have PSU's that are running fine from those days.

Yep, my server and my controller run fine that way.
 

SaurusX

Senior member
Nov 13, 2012
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I just built my new rig with the Silverstone TJ08B-E and the PSU is mounted at the top in that case with the fan pointing up so that it's pulling in outside air. My old case also had the PSU at the top, but the fan was pointed down pulling air from the inside. Just throwing that out there for informational purposes.
 

Ketchup

Elite Member
Sep 1, 2002
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I just built my new rig with the Silverstone TJ08B-E and the PSU is mounted at the top in that case with the fan pointing up so that it's pulling in outside air. My old case also had the PSU at the top, but the fan was pointed down pulling air from the inside. Just throwing that out there for informational purposes.

That case mounts the motherboard upside-down, so that would make sense to me.
 

Ketchup

Elite Member
Sep 1, 2002
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Perfect! Yet the TJ08-E and PS07 manual (Page 6) suggests the opposite..."fan facing down". There you have it, it makes no difference. END OF THREAD


Interesting the picture on that page shows the fan facing up.

The outcome of both is the same - the heat generated by the pc will not affect the air going through the power supply, which could be a killer.
 

VirtualLarry

No Lifer
Aug 25, 2001
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I tend to put the PSU at the bottom, with the fan facing UP. Just be careful not to drop any screws into the PSU!