Should My PSU Face Down Or Up?

T

TheMusketeer

Gawd
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So I have a NZXT 210 Source case, and I was wondering should I mount the psu (fan facing up) up or psu (fan facing down) down? I have x2 fans intaking air in from the front and x3 fans exhausting air out the case. I know that it is better to mount the psu fan facing down; however, I absolutely hate dust building up; therefore I mounted the psu fan facing up. Will this reduce the life of the PSU? Should I worry about it?

Thanks
 
Fan side down. Too easy to drop things inside a PSU with the fan side facing up.
 
Dangman said:
Fan side down. Too easy to drop things inside a PSU with the fan side facing up.
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Other than having things drop inside the PSU, are there any real tests that prove mounting the PSU up or down is better? I haven't found any articles about this?
 
ilal2ielli said:
^ This is the reason why you don't see tests.
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For some reason I read a lot other threads on other sites that say that the PSU need to intake air from the bottom (cool air) to cool the PSU. Are they just making it up? I'm just a bit paranoid that's all.
 
TheMusketeer said:
Other than having things drop inside the PSU, are there any real tests that prove mounting the PSU up or down is better? I haven't found any articles about this?
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No not really. Assuming you have equal airflow above and beneath the PSU, it makes zero difference.
 
TheMusketeer said:
For some reason I read a lot other threads on other sites that say that the PSU need to intake air from the bottom (cool air) to cool the PSU. Are they just making it up? I'm just a bit paranoid that's all.
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Prior to the bottom mount, all PSUs were top mounted and sucking in case heated air. A lot of Dell's, HP's, and other prebuilt manufacturer systems still have top mounted PSUs.

Anything will run more efficient when its cooler, but is it necessary? Not at all.

Read reviews of PSUs in a hotbox that recycle the exhaust air back into a closed system to see that this is the case.

IIRC, [H] does hot load tests and JonnyGURU definitely does.
 
Thanks for all the comments. I sort of got paranoid after reading some reviews. As for the distribution of airflow, I have two intakes in front and I have two exhaust on top and rear. I also have a low end graphic card with the fan facing the psu fan. I guess my system won't even get that hot, other thatn the fact I have 8 hard drives which wouldn't even be in operation only when I am transferring files to them.

Do you think my fan distribution is correct?
 
Facing up would increase PSU temps / PSU fan speed if it has a variable speed controller. It would also help move more air out of the case and might make your other fans ever so measurably quieter (probably not noticeable, really depends on your PSU and heat in the case as well). Facing down gives the PSU cooler air letting the PSU fan spin slower.

I personally prefer to mount them 'fan-up' to help normalize fan speeds across all the fans during heavy heat loads. This is less of an issue with a water cooling setup. But my entire setup is this paradigm: CLC cooler exhausting air, GTX 670 FTWs with blower coolers for exhausting air, etc. Good PSUs wont mind some hotter air on the intake at all.

The situation where 'face-up' would help the most would be if you have slow non-variable fans in the case. You'd now have more area to move the air out of the case AND another fan helping move it.

What case do you have?
 
Fan up or down depends on the case and components. For cases with PSU at the bottom, I always mount the PSU fan-down when I can. Like Dangman said, I don't want to drop any screws into it by mistake. I probably would, too. It's probably better for airflow to face it up in many of these cases... My Fractal Design Define R4 has a grille for airflow on the bottom, but its efficiency is significantly reduced when using it on carpet as I currently am. Still enough airflow there (and there's some airflow to the PSU from the case itself) but not the most ideal. I'll take it over the screw. It'd be better if I had wood floors.

Fan-down usually for top-PSU cases, too, but this time just because it's usually better for airflow in such cases anyway.
 
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Face down for me if the PSU is bottom mounted and the case has a vent for it. That way it is getting cooler air and is not fighting my CPU and GPU for air.
 
in a case with vents at the bottom I'd have a hard time imagining why one would want to mount the PSU facing up to get stuff dropped into it... and to have it sucking hot air all day...meh

maybe if the case is going to sit on carpet... in my case (no pun intended) partly because my NZXT H630 is so massive and partly to keep it off the rug i built this little dolly for it with a shelf from the hardware store and 4 caster wheels

 
Airflow gets priority. If you're concerned with dropping things in the PS install the it last.
 
mi7chy said:
Airflow gets priority. If you're concerned with dropping things in the PS install the it last.
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Why? The airflow through my PSU is sufficient enough as-is and I would gain nothing by further increasing it. I mean I can always put a sheet of paper over the PSU if I work on the PC, but there's no need.
 
Perhaps having data center experience makes one more conscious of natural airflow. Considering that heat naturally rises it's kind of backasswards for some of the newer cases that mount exhaust-through-back PS at the bottom and then making it work harder by putting the intake nearly flush against the chassis with a little gap. You might get away with it in a tiny mITX case with no volume but it would be suicide with a 42U server enclosure forcing that volume of hot exhaust unnaturally the opposite direction especially when the Lieberts go offline.
 
mi7chy said:
Perhaps having data center experience makes one more conscious of natural airflow. Considering that heat naturally rises it's kind of backasswards for some of the newer cases that mount exhaust-through-back PS at the bottom and then making it work harder by putting the intake nearly flush against the chassis with a little gap. You might get away with it in a tiny mITX case with no volume but it would be suicide with a 42U server enclosure forcing that volume of hot exhaust unnaturally the opposite direction especially when the Lieberts go offline.
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I don't think anyone disagrees that server rack cooling is a different beast, but it doesn't mean that every single PC needs to be prioritize airflow first, or otherwise our home PCs would all be ridiculously loud. Of course, it depends on the case as well. I feel my Define is good enough even on carpet, but some cases might have even less airflow on the bottom.
 
It really doesn't make that much of a difference, my rule of thumb is if the case is bottom mounted, has vents underneath, and the case is not right ontop of a carpet, then to face it down.
 
Does the case even let you mount it either way? mine only allows for fan-facing down
 
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