Is it better for zero RPM PSUs to place the fan on top?

[few34fwfs]

So I've heard that if the PSU has a zero RPM mode then it's better to place the fan on top for better heat dissipation.
What do you think about that?

 

[DaemonForce]

Depends on the orientation. I still use a 750W Antec from the old era and have torn through it to replace the single 135mm fan twice.
It's typically in a downward position to pull air from the case and belch it out the side(rear).
I've experimented with flipping the mount bracket and PSU when doing some radiator crossflow. I don't notice a difference.

 

[#22]

It's a matter of simply doing what manual suggests. E.g. Seasonic recommends to install their semi-passive PSUs with fan on top. And if you do opposite, some turn off due to OTP. On the other hand I've happened to once ask Corsair what about one of their older units and they told me it's best to install it with fan on the bottom due to access to fresh air. And I personally have mine with fan on the bottom for more than a year. No problems and I've never heard it what further suggests everything's fine. I've also once serviced computer with passive PSU mounted upside-down what is the worst you could do to such and it has been working like that for 5-10 years and be totally fine at least with new hardware I've tested it. It's all about the heat and quality PSUs handling it better.

 

[AusWolf]

Depends on the orientation.

This.
If your PSU is on the top of the case, then naturally, make its fan face down to use the natural airflow of the case.
If it's on the bottom, then you can have it either way, I guess.
If it's on the bottom, but in a separate compartment, then facing the fan up would only choke the PSU.

Personally, I have my PSU's zero RPM mode disabled, as being in a separate compartment, my PSU receives zero airflow from the environment, making it heat up even when the PC is idle.

 

[Assimilator]

Presumably the rationale in mounting a PSU with its fan facing upwards is that the fan grille will thus be facing upwards too, so hot air will be able to escape from the unit into the chassis, therefore allowing a longer duration of passive operation. I would question this assumption as PSUs are often designed with fan baffles to direct the airflow, and in a fan-upwards configuration such a baffle would block some of the hot air from rising out the grille.

Mount the PSU in the orientation its manufacturer tells you to. It has been designed with the assumption that it will be operated in that orientation and if you do otherwise, any engineering optimisations implemented regarding cooling are no longer valid.

 

[#22]

Personally, I have my PSU's zero RPM mode disabled, as being in a separate compartment, my PSU receives zero airflow from the environment, making it heat up even when the PC is idle.

Seeing Seasonic in your Specs I'm not surprised and it gives me additional thought. Seasonics are known for primitively working semi-passive operation with fan turning on and off crossing the same temperature and to make things worse doing it in loud manner. Imo unnaceptable thing and I also wouldn't accept as solution switching it to active operation. But if somebody just happened to get such PSU with no option to change it, placing PSU with fan up to reduce heat build-up may help with such problem.

 

[ARF]

So I've heard that if the PSU has a zero RPM mode then it's better to place the fan on top for better heat dissipation.
What do you think about that?

Where have you heard that from, and based on what logic?

This.
If your PSU is on the top of the case, then naturally, make its fan face down to use the natural airflow of the case.

The thing is that the hot air from the case will be pulled in the PSU, which I guess will warm it up by several additional degrees °C.

If it's on the bottom, then you can have it either way, I guess.
If it's on the bottom, but in a separate compartment, then facing the fan up would only choke the PSU.

Personally, I have my PSU's zero RPM mode disabled, as being in a separate compartment, my PSU receives zero airflow from the environment, making it heat up even when the PC is idle.

Depends on the case. If there are perforations on the compartment top wall, then the fan will push the air towards the graphics card.*
*If not pull hot air from the area under the graphics card in downwards direction...

 

[few34fwfs]

Where have you heard that from, and based on what logic?



The thing is that the hot air from the case will be pulled in the PSU, which I guess will warm it up by several additional degrees °C.



Depends on the case. If there are perforations on the compartment top wall, then the fan will push the air towards the graphics card.*
*If not pull hot air from the area under the graphics card in downwards direction...

I heard it on YouTube from a PSU Guru based in the logic that the hot air goes up.

 

[ARF]

I heard it on YouTube from a PSU Guru based in the logic that the hot air goes up.

Yes, but the fan is not an obstacle.
Actually, fresh* air is pulled in and then it escapes from another wall, like in the image, blue arrow bottom of PSU, red arrow rear of PSU:

 

[few34fwfs]

Yes, but the fan is not an obstacle.
Actually, fresh* air is pulled in and then it escapes from another wall, like in the image, blue arrow bottom of PSU, red arrow rear of PSU:

View attachment 345578

Exactly the point. The fan is not an obstacle but the opposite metallic side of the PSU is. We are talking about zero RPM always right?

 

[ARF]

Exactly the point. The fan is not an obstacle but the opposite metallic side of the PSU is. We are talking about zero RPM always right?

Which particular PSU? There are passive (fanless) and semi-passive (with a fan which spins up at 40-50% a certain threshold).
I guess the PSU itself has an instruction about how to use it.

PRIME TITANIUM FANLESS

Seasonic PRIME TITANIUM FANLESS completely silent PSU operates without fans and boasts a titanium efficiency rating, ensuring optimal heat reduction.

seasonic.com

 

[dirtyferret]

So I've heard that if the PSU has a zero RPM mode then it's better to place the fan on top for better heat dissipation.
What do you think about that?

if you have a good PSU it will make little difference, I can make an argument for either orientation.

I heard it on YouTube from a PSU Guru based in the logic that the hot air goes up.

With no airflow, hot air rises slowly. Most people have at least one fan in their case so "hot air" will go in the direction you send/pull it. Also don't confuse hot air with heat as heat spreads. And what is a Toutube PSU guru? Is that like a webmd forum health guru? Cause I went to webmd on how to treat an itchy mosquito bite and now I may have up top ten different forms of cancer...and ringworm!

Yes, but the fan is not an obstacle.
Actually, fresh* air is pulled in and then it escapes from another wall, like in the image, blue arrow bottom of PSU, red arrow rear of PSU:

nothing worse then air getting fresh, you have to nip that in the bud or the comments just cut to the bone

 

[Bill_Bright]

So I've heard that if the PSU has a zero RPM mode then it's better to place the fan on top for better heat dissipation.

Where did you hear this? Got a link?

For sure, RTFM. That said, IMO, from a technical viewpoint it does not matter (with one exception - see below). Why? Because if/when the PSU's temperature rises above its preset threshold to start the fan spinning, the fan will start spinning. And the force of the air movement cause by the spinning fan will quickly negate any "heat rises" effect and the PSU will cool, and stay cool appropriately.

The exception? If the PSU mounts at the top of the case, then the PSU's vent (fan intake) should be down, regardless if zero RPM or not - unless (this is the exception to the exception) the top of the case is open and/or has a free-flow vent above that spot to let air exhaust out the case. Otherwise, the cramped space between the top of the PSU and the computer case at that point may trap heat and hinder adequate air flow through the PSU and ventilation out the computer case, even when the fan is spinning.

 

[few34fwfs]

Where did you hear this? Got a link?

For sure, RTFM. That said, IMO, from a technical viewpoint it does not matter (with one exception - see below). Why? Because if/when the PSU's temperature rises above its preset threshold to start the fan spinning, the fan will start spinning. And the force of the air movement cause by the spinning fan will quickly negate any "heat rises" effect and the PSU will cool, and stay cool appropriately.

The exception? If the PSU mounts at the top of the case, then the PSU's vent (fan intake) should be down, regardless if zero RPM or not - unless (this is the exception to the exception) the top of the case is open and/or has a free-flow vent above that spot to let air exhaust out the case. Otherwise, the cramped space between the top of the PSU and the computer case at that point may trap heat and hinder adequate air flow through the PSU and ventilation out the computer case, even when the fan is spinning.

Yeah I know but he makes an argument that the fan starts spinning when PSU is already too hot. That's a general argument not for the RMx.
He doesn't speak in that video in English you wouldn't understand.
Anyway since I'm getting the Shift it's also a convince for me to put it with the fan on top since I wouldn't have to cut a hole through my case's metal sheet that holds the MB to get to it's sockets. From the other hand cable management wouldn't be so nice.
I haven't decided yet.

 

[dirtyferret]

Yeah I know but he makes an argument that the fan starts spinning when PSU is already too hot.

If that's true then you bought a poorly designed PSU. The fan should turn on and/or spin faster as the PSU gets warmer.

That's a general argument not for the RMx.

um, what argument?

 

[Panther_Seraphin]

SO looking at it purely from a setup where the PSU is isolated from any sort of additional airflow then yes having the fan facing up will increase the amount of time before the fan turns on and in theory would reduce slightly the amount of time before it turns off. This is because there is no case and no PCB trapping heat in and via convection the unit will generate a minimal amount of airflow on its own.


If you are in a situation where you have a decent amount of airflow (aka already louder than what the PSU fan omits when running) then having it in the path of that airflow would be enough, but that defeats the point of the zero rpm mode IMO.

If you are in a system really designed for minimal noise where zero RPM is "intended" for, the airflow through the system probably wouldnt be enough to overcome the "stagnant" air around the particularly hot components in a PSU leading to either localised hotspots or short cycling of the fan to cool down those areas as needed when orientated in the normal way.

 

[Bill_Bright]

Yeah I know but he makes an argument that the fan starts spinning when PSU is already too hot.

Who is he? I ask again, where did you read this? Got a link?

How do you know what languages I and others understand or speak?

If that's true then you bought a poorly designed PSU. The fan should turn on and/or spin faster as the PSU gets warmer.

Exactly that - on both points. With any decent, properly designed, properly functioning PSU, the fan "WILL" spin up (or spin faster) BEFORE it gets too hot.

That's a general argument not for the RMx.

No its not. If that were true, it would be reported in a widespread manner across the industry. Even in English!

The truth is, PSUs with zero RPM fans, have become very popular simply because they work and they work well.

 

[few34fwfs]

Who is he? I ask again, where did you read this? Got a link?

How do you know what languages I and others understand or speak?


Exactly that - on both points. With any decent, properly designed, properly functioning PSU, the fan "WILL" spin up (or spin faster) BEFORE it gets too hot.


No its not. If that were true, it would be reported in a widespread manner across the industry. Even in English!

The truth is, PSUs with zero RPM fans, have become very popular simply because they work and they work well.

I say that is a general argument and then you tell me I bought a poorly designed PSU...
I say that is an argument and then you tell me that it's not?!
How can this be?
An argument is an argument.
It has nothing to do if it's truthful or not.

 

[dirtyferret]

I say that is a general argument and then you tell me I bought a poorly designed PSU...
I say that is an argument and then you tell me that it's not?!
How can this be?
An argument is an argument.
It has nothing to do if it's truthful or not.

I'm not sure what your argument is. The RMx is an excellent unit that was designed to run in either active or semi active fan mode. It works properly in each mode as per design. To simply have an "argument" over something as generic as active vs semi active without specific units is like having an argument between soup vs bisque. Which one, who made it?

 

[Bill_Bright]

An argument is an argument.
It has nothing to do if it's truthful or not.

What? This is a "technical" support forum. It is all about the "technical facts". Do you not understand what a fact it? It is all about the truth.

I say that is a general argument and then you tell me I bought a poorly designed PSU...

No I didn't. You are not being "truthful". First, it is not a "general" argument. It may be your opinion, but not a proven fact. And second, I never said you bought a poorly designed PSU. I was agreeing with dirtyferret who said "IF" your mystery man was telling the truth, then you bought a poorly designed PSU.

I say that is an argument and then you tell me that it's not?!

No you didn't. Again, you are not being truthful. You said it was a "general" argument. A general argument is one that is "generally" considered to be factual. In other words, it would be a "widespread" belief to be true or factual. But you have shown zero evidence this is a widespread or general argument. It is simply you claiming some mystery person said something. That means nothing.

You cannot just post comments claiming them to be facts without some sort of supporting evidence. You have provided none.

You might want to read dirtyferret's signature line. And the line in my sig about opinions and doing your homework.

 

[#22]

Yeah I know but he makes an argument that the fan starts spinning when PSU is already too hot. That's a general argument not for the RMx.
He doesn't speak in that video in English you wouldn't understand.
Anyway since I'm getting the Shift it's also a convince for me to put it with the fan on top since I wouldn't have to cut a hole through my case's metal sheet that holds the MB to get to it's sockets. From the other hand cable management wouldn't be so nice.
I haven't decided yet.

If Shift, I'll add that it's the PSU I mentioned using for more than a year with fan down - RM1200x to be exact. Whole Shift family are one of my favourite units. Not the best for the price performance-wise, but good to the point such differences being negligible and they are super-quiet what is the only aspect of PSU you will be noticing on daily basis. Like I said, I've never heard it, because capacity, but also starting it's fan with inaudible manner what it shows when turning pc on. Cables on side coming in handy during maintenance and better executed 12VHPWR are also nice. Totally recommend

 

[few34fwfs]

What? This is a "technical" support forum. It is all about the "technical facts". Do you not understand what a fact it? It is all about the truth.


No I didn't. You are not being "truthful". First, it is not a "general" argument. It may be your opinion, but not a proven fact. And second, I never said you bought a poorly designed PSU. I was agreeing with dirtyferret who said "IF" your mystery man was telling the truth, then you bought a poorly designed PSU.


No you didn't. Again, you are not being truthful. You said it was a "general" argument. A general argument is one that is "generally" considered to be factual. In other words, it would be a "widespread" belief to be true or factual. But you have shown zero evidence this is a widespread or general argument. It is simply you claiming some mystery person said something. That means nothing.

You cannot just post comments claiming them to be facts without some sort of supporting evidence. You have provided none.

You might want to read dirtyferret's signature line. And the line in my sig about opinions and doing your homework.

Dude it's an argument.i didn't say it was untruthful. You did. Your capacity to comprehend is limited.

 

[Bill_Bright]

Dude it's an argument.i didn't say it was untruthful. You did. Your capacity to comprehend is limited.

OMG! Your capacity to understand technical discussions, and perhaps, even your own words, is nonexistent.

You specifically said,

An argument...has nothing to do if it's truthful or not.

That in itself is untruthful!

Again, this is a technical support forum with the primary goal of informing readers of the technical "facts". That is, the truth!

And now, in some wayward attempt to rationalize your own comments, are you seriously going to "argue" that it is okay if your position is not the truth? Really? You have pretty much defined yourself as a forum troll.

****

You asked a question about placement of PSUs. You received several replies, all saying, more or less, the same thing. I suggest you read those responses, heed their advice, and move on.

Now I am moving on.

 

[few34fwfs]

OMG! Your capacity to understand technical discussions, and perhaps, even your own words, is nonexistent.

You specifically said,

That in itself is untruthful!

Again, this is a technical support forum with the primary goal of informing readers of the technical "facts". That is, the truth!

And now, in some wayward attempt to rationalize your own comments, are you seriously going to "argue" that it is okay if your position is not the truth? Really? You have pretty much defined yourself as a forum troll.

****

You asked a question about placement of PSUs. You received several replies, all saying, more or less, the same thing. I suggest you read those responses, heed their advice, and move on.

Now I am moving on.

You shouldn't engage in conversations if you are unwilling to accept that your position might be wrong. That is pointless. And that is exactly what you are doing. Your facts are facts only in your mind.
As for me I can't be wrong because I didn't express an opinion. I merely asked you to comment on something.

 

[dirtyferret]

You shouldn't engage in conversations if you are unwilling to accept that your position might be wrong. That is pointless. And that is exactly what you are doing. Your facts are facts only in your mind.
As for me I can't be wrong because I didn't express an opinion. I merely asked you to comment on something.

1. Bill's not wrong
2. His facts are accurate
3. You asked a question based on incorrect information. Bill simply answered your query with correct information. Not sure why you are reacting in the way you are reacting.