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Debate: PSU fan - face up or down?

nightrook

24 months ago

As the title states.

I am in an argument with someone and I just want to know all your points of views. Hit me with all the opinions!

I will say that I don't believe there's an answer that's right all the time; it depends on the situation and the case and other factors.

Anyone up for debating? It's frustrating when someone won't listen to you so this is a nice way to vent.

Comments

  • 24 months ago
  • 3 points

Fan down, so the PSU takes cool air through the case's bottom intake and exhausts it out the back.

If the case's bottom hole is obstructed (like with a thick carpet), then fan up. That way the PSU takes hotter air from the inside of the case, so some internal components may last less time.

  • 24 months ago
  • 1 point

See, this is exactly my point of view. Would the presence of dust filters change anything for you? What about cases with a separate compartment for the PSU? Non-ATX cases where the distance between the video card and the PSU are much smaller?

  • 24 months ago
  • 1 point

depends on the case layout. Most modern cases have a fan filter for the psu at the bottom for intake so psy fan down (most of the time).

  • 24 months ago
  • 1 point

When would you say to put the fan facing up? What about cases that have the PSU sectioned off?

  • 24 months ago
  • 1 point

When would you say to put the fan facing up?

A brilliant example, of mounting the PSU upside down, otherwise temps would be higher on small factor and similar Cases, and the PSU would also work at higher temps.

https://static.techspot.com/articles-info/959/images/Image_12S.jpg

Besides - as you can see, that particular Case has vents at the top for that very reason.

https://static.techspot.com/articles-info/959/images/Image_09S.jpg

Note: The Case in question is the **Silverstone Sugo SG13 Mini-ITX.

  • 24 months ago
  • 1 point

Haha okay, fair point. So essentially you don't like it when the PSU pulls are from inside the case. :P Thanks for the comments!

  • 24 months ago
  • 2 points

So essentially you don't like it when the PSU pulls are from inside the case.

Well, not exactly. :-P

If you must mount it on a Case that has plenty of space why not?

Of course if the Case is sitting on a carpet the Case does not even have a dust filter, and you are forced to mount the PSU on the bottom chamber, sometimes it would be the better idea to mount it that way, that the fan is facing up.

That's why some cases have open vents on that matter.

Example: http://www.funkykit.com/wp-content/uploads/2017/01/P400-11-1a.jpg - <Phanteks Eclipse P400 TG>

However...if you have in mind to go AIO, i would suggest to mount the PSU with the fan facing down. (if possible)...

So, why facing down?

If, and i say only IF...something bad happens on the AIO and cooling fluid drips inside the Case, the last thing you want is having an PSU mounted with the fan facing up.

It would mess up your day. lol

  • 24 months ago
  • 1 point

Hmm.. I like you. Thanks for the input!

  • 24 months ago
  • 1 point

depends on where the fan intake for the psu is, but if it had both, then down. since heat rises, that would make the most sense.

  • 24 months ago
  • 1 point

Huh, that's interesting, I never thought about the heat rising. I was more focused on the flow of air, but heat does play a part. Thanks for the comment!

  • 24 months ago
  • 1 point

Most PSU fans don't even spin nowadays unless you have an older model, buy bargain bin or you have 3x GPUs. I'd rather have the fan facing up so it can catch gentle airflow from the intake fans on the top of the case instead of dead air under the case.

  • 24 months ago
  • 1 point

I'd rather have the fan [on the PSU] facing up so it can catch gentle airflow from the intake fans on the top of the case instead of dead air under the case.

Intake on the top of the case? Intakes typically go to the front and bottom of the case and exhaust on the top and rear of the case. Hot air rises, so why fight physics and gravity?

  • 24 months ago
  • 2 points

I like having all intakes with the only exhaust being the back. If you have the tops as exhaust then there's definitely going to be negative air pressure which will just create a big pile of dust.

  • 24 months ago
  • 1 point

If you have the tops as exhaust then there's definitely going to be negative air pressure

It is not necessarily so.

All you have to do is balance them with the same amount of air intake. E.g. if you have 2 intakes on top and 1 on the rear you place 2 intakes in the front and 1 on the bottom. There you go, neutral air pressure.

Or 2 on the bottom / 3 as intakes, if you insist to positive air pressure, which is not needed as neutral is just fine to prevent air /with dust/ being sucked in through every gap and opening on the case.

  • 24 months ago
  • 1 point

Most cases don't have fan mounts on the bottom. Especially newer cases that are coming with shrouds over the basement/psu area. My case can do 3x 120s in the front 3x 120s in the top and 1x 140 in the rear. If I did the top as exhaust, I'd surely have negative airflow.

I also have a Noctua D15S which has 2x 120mm fans pointed to the rear, so that pretty much acts as an exhaust too to direct the airflow out.

  • 24 months ago
  • 1 point

Of course, every case is different. All I was saying is that using the top of the case as exhaust doesn't automatically generate negative airflow.

  • 24 months ago
  • 1 point

Zero RPM mode can make this question irrelevant. :)

Zero RPM mode is when the PSUs fan does not spin at all unless it's needed. Mine has never started, though I have it for about 2 years now.

  • 24 months ago
  • 1 point

The point is that the fans do spin, otherwise there would be no debate.

  • 24 months ago
  • 1 point

Well, those cases have been covered by others. :)

I wanted to point out that newer models might not have their fans spinning all the time or at all.

  • 24 months ago
  • 1 point

Fair enough.

[comment deleted by staff]
  • 24 months ago
  • 1 point

What if there were no dust filters?

[comment deleted by staff]
  • 24 months ago
  • 1 point

Thanks for the comments!

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