Bottom Mounted PSU, fan facing Up or Down?

litwicki23 · Oct 22, 2014

Hi everyone,

- PSU: FX XXX Edition Pro Modularny 80Plus Bronze - 750W (P1-750X-XXB9)

http://www.morele.net/zasilacz-xfx-xxx-edition-pro-modularny-80plus-bronze-750w-p1-750x-xxb9-554274/

- case: Centurion 590

http://www.coolermaster.com/case/mid-tower/centurion-590/

Question: Should this PSU be mounted with the fan facing UP, or Down, or it doesn't matter?

The PSU mounts on the bottom.

Newbbuilder11 · Oct 22, 2014

It depends if the case has a fan mount facing down, if it does you can mount it upside down since having it upside down brings cooler air in and then out making your PSU run cooler. If it doesn't then it's still ok as it will help bring out some hot air in the case and bring it out the back.

Either-way it totally depends on your case

.

I have my PSU facing down to bring in colder air in it and then out, but their is nothing wrong with it facing up.

But be sure your case can do this first of all.

CONS of having face down: Dust could get in and choke your PSU so make sure you have a fan filter facing down.
PROS: Cooler air for your PSU so it won't get hot.

PROS facing up: No dust get's in the fan(If you keep your case clear)
Cons: Using warmer air to cool it(not really a con.. but w/e).

capt_taco · Oct 22, 2014

You're supposed to have the fan facing down so it can pull cool air in from outside the case.

If you have the fan facing up, it will be pulling hot air in from inside the case, as well as fighting the exhaust fans and the overall airflow of the case.

Any case with a place for a bottom-mounted PSU will have a vent at the bottom to allow air in from underneath. Your case doe as well (4th picture). It's there for a reason; use it.

Newbbuilder11 · Oct 22, 2014

capt_taco :

Not necessarily no, if you have a GPU facing down and a PSU facing up it actually sucks out the GPU hot air and cools it down better as the GPU.

I know from experience, I had a PSU face up and had great cool temps, switched down and hardly notice any difference by like 1-3 Degrees,

And in a way actually helps suck out hot air from the case

ccampy · Oct 22, 2014

If your GPU fans face down and your pau faces up this will effect each other as they are trying to pull air against each other on different directions

capt_taco · Oct 22, 2014

ccampy :

Exactly what I was going to say. Hot air from the GPU is blown out the back, not the bottom. Having a PSU with the intake on top will just pull air away from the GPU's intake, and vice versa, making it harder to cool both.

A downward-facing PSU remains essentially isolated from the rest of the case airflow, pulling cool air in from the bottom and blowing it right out, without interacting with anything. Just lets the rest of the cooling components do their job. Definitely the way to go if you ask me.

edit: a bottom-mounted PSU with the fan facing up also won't suck hot air out of the case. Hot air rises to the top to be blown out by an exhaust fan. What it WILL do is prevent a lot of cooler air from the front fans and/or side fans from reaching the CPU and GPU.

litwicki23 · Oct 22, 2014

Finally, capt_taco so you reccommend me mounting PSU with the fan facing down? Yes? Even if its on carpet yes?

Here is my screen:

http://s11.postimg.org/4qkeu56tv/image.jpg

Case is on carpet. Is this really matter on my situation ?

capt_taco · Oct 22, 2014

Hmm. Well, it'd be better if it was on a surface that wasn't so full of dust.

I still think facing down is the way to go - just get a fan filter to go over that bottom intake, or better yet, put one of those hard flat plastic mats under your machine. That should solve it.

You can still do it anyway ... after the initial dust barrage, you probably won't get a heck of a lot more dust than on another surface, since the carpet won't be gathering any new dirt where your machine is sitting on top of it. One of the other two solutions would be better, though.

litwicki23 · Oct 22, 2014

But somebody told me that if i say that i want use PSU with fan facing down.

"would u rather it take in heated, dusty Still air from your carpet?"

capt_taco · Oct 22, 2014

It's not going to be taking in heated air from underneath the case. It's outside air, which is going to be cooler than what's inside the case.

"Still" shouldn't make any difference at all - the air isn't being pushed sideways across the front of the fan, so what. The fan is more than powerful enough to pull in the air it needs, and it will be flowing quite fast when it comes out the other side of the fan and reaches the components, which is what matters.

The only thing I'd be somewhat concerned about is the possibility of dust. But as mentioned earlier, there are ways to lessen that. Unless it's a deep carpet that gathers mountains of dirt, I'd try to do it that way. If it's too big of a problem, then yes, you can point it with the fan up and it will still work fine; you just may be sacrificing a bit on CPU and GPU temperature, so pay attention to those.

litwicki23 · Oct 22, 2014

Look, here is my carpet:
http://s11.postimg.org/4qkeu56tv/image.jpg

Actually my psu is mounted with fan facing down. Case is on carpet. Its ok or its any risk to damage PSU because it is on carpet?

capt_taco · Oct 22, 2014

I wouldn't worry about it too much, just clean it out more frequently if you're concerned.

As I said, you can take steps to mitigate the dust concerns - filters, raise the case up a couple inches, put something under it - plastic mat would work, but for that matter, you can just flatten out a cardboard box if you want.

Top-facing just has too many issues to make it worth it most of the time. Plus, if you're opening up your machine and you drop a screw in there, bad news. Another reason why it's good to have the PSU fan facing down.

litwicki23 · Oct 23, 2014

But what if my carpet is clean, without powder and hairs. So then my case can be at carpet with psu with fan facing down? Its not dangerous?

litwicki23 · Oct 23, 2014

Somebody told me:

"Face fan down:

PSU pulls air from under case and exhausts out the back, fan may be blocked by not enough air flow and could die."

So why many peoples have psus with fan facing down?

Newbbuilder11 · Oct 23, 2014

litwicki23 :

Usually because they do not have great filters and choke and die, that is why it's best to keep it in a place free from carpet and stuff like on a desk and has a great filter. That is why you make sure it's always clean.

Now, if you have a room that is all carpet and no room on your desk it's fine to face it up since it won't really affect anything in your case. I know from experience it's perfectly fine to have it face up if you are worried and actually can help remove heat from your case. I have my PSU face down but that's because my Case has two bottom dust filters and has an extension to lift it off the carpet.

capt_taco · Oct 23, 2014

litwicki23 :

Well, obviously the cleaner the carpet is, the better. Dust can come from anywhere, even a bare wood floor. But a downward facing fan can still pull in carpet fibers and lint, which can be an issue if there's a lot of it in your carpet. You're going to have to be the one who's the judge of that.

But as I said, there are some pretty easy ways to keep the dust from getting in there even with a downward-facing fan; the poster right above me has two of them going.

litwicki23 · Oct 23, 2014

Ok finally . I want to ask you guys. Is here enough room for airflow to the fan in my psu? Here are the screens what is looking :

( first screen are my pc ) Is here enough room for airflow to the fan in my psu here?

http://postimg.org/image/6e4ehgwm1/50166c5e/ I must change something here for improve better airflow or it can be like it is?

http://s29.postimg.org/65upqsqef/centurion590.jpg

( second screen is not my screen, but position is the same like on psu )

capt_taco · Oct 23, 2014

There's enough room for airflow. You don't need much, less than an inch will do. Raise it up further if you're still worried about dust, and get that cat out of there.

litwicki23 · Oct 23, 2014

The most important question. Is here enough room for airflow to the fan in my psu? There is enough room under the case to provide air to PSU?
Screen from my case :
http://s12.postimg.org/ogxh8osgt/image.jpg

Dark Lord of Tech · Oct 23, 2014

Yes that is enough room.

litwicki23 · Oct 23, 2014

I will add to my case non reference card Asus Gtx 980 Strix with 2 fans. So question now. Which way of plug PSU will be better,with fan facing up or facing down? For better airflow overall i mean. Damn i am confused. !

Dark Lord of Tech · Oct 23, 2014

Always face the fan down when you have even the smallest area of ventilation.

Keeps your setup cooler.

litwicki23 · Oct 23, 2014

Sorry guys but i am really confused. Somebody told me that:
"You will choke it with the fan facing downwards."

It can be true?

Dark Lord of Tech · Oct 23, 2014

No that's wrong , bad information.

Fan down is right.

litwicki23 · Oct 23, 2014

The most important question. Is here enough room for airflow to the fan in my psu? There is enough room under the case to provide air to PSU?
I need to add some material between the carpet and the bottom of the case? ( like sheet of cardboard, a piece of wood, or book )
I must raise the case up a couple inches and put something under it? Or not? What you think about that?

Bottom Mounted PSU, fan facing Up or Down?

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