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Discussion Starter · #1 ·
How detrimental in the long run would it be to orient a PSU with its intake fan inside the case, taking warmed air in from the case, not far from a non reference GPU (HD 7970) and exhausting it out of the case? Detrimental to the PSU, that is. I know the best way to orient a PSU would be to exclude it from case air circulation completely and allow it to get fresh air from outside the case. But in the worst case scenario, if I had to flip it and have the intake fan face the GPU, would I ruin the PSU?

The GPU runs as warm as 69C under load.

PSU in question is a PC Power & Cooling Silencer MK II 750 Watt. And possibly a Corsair AX750, if I switch to that.
 

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It would be detrimental if you were to put it in a dusty place. I have a CM Cosmos and i have fliped it to take fresh air from outside but i padded the intake mouth with filter paper to get those heavy dust out of the way
 

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No, because your highest possible power draw with this setup is about half the capacity of this PSU. That means it's never going to get too hot.
 

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Yeah, what TwoCables says is correct. As long as you keep your case fairly clean (so the PSU doesn't turn into a vacuum for your case) you should have no problem with it at all.
 

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Take a moment to remember than every single power supply ever was oriented with it's intake inside the chassis until a few years ago, and most still are, and you will have your answer.
 

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Discussion Starter · #6 ·
Thanks to everyone who replied! This will allow me to have better overall airflow in my modded case, and should bring GPU temps down a bit too. No dust issues, as I clean everything regularly.
 

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Discussion Starter · #7 ·
Additional question, having re-read the replies: what about PSUs that have fan curves assigned to PSU loads? And maybe the PSU fan won't even turn on until I draw 200 Watts--which can happen with my system while in some games. Such CPUs are meant to be cooled in a certain way when a certain amount of current is drawn to cool resulting generated heat. But if I don't draw enough current for how warm the PSU gets due to the additional heat from the GPU exhaust, it's still pretty safe? Basically only efficiency would suffer? I suppose that is why there are "hotbox" results for some PSU reviews.
 

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Quote:
Originally Posted by ElevenEleven View Post

Additional question, having re-read the replies: what about PSUs that have fan curves assigned to PSU loads? And maybe the PSU fan won't even turn on until I draw 200 Watts--which can happen with my system while in some games. Such CPUs are meant to be cooled in a certain way when a certain amount of current is drawn to cool resulting generated heat. But if I don't draw enough current for how warm the PSU gets due to the additional heat from the GPU exhaust, it's still pretty safe? Basically only efficiency would suffer? I suppose that is why there are "hotbox" results for some PSU reviews.
I again refer you to my last post.
 

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Quote:
Originally Posted by ElevenEleven View Post

Additional question, having re-read the replies: what about PSUs that have fan curves assigned to PSU loads? And maybe the PSU fan won't even turn on until I draw 200 Watts--which can happen with my system while in some games. Such CPUs are meant to be cooled in a certain way when a certain amount of current is drawn to cool resulting generated heat. But if I don't draw enough current for how warm the PSU gets due to the additional heat from the GPU exhaust, it's still pretty safe? Basically only efficiency would suffer? I suppose that is why there are "hotbox" results for some PSU reviews.
I wouldn't worry. Most good psu's don't even get all that hot on their own anyway, and as long as you have a decent amount of airflow in your case, you'll have no problem at all.

Most top builders have their PSU facing inwards for looks, and none of them ever report problems.
 

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Discussion Starter · #10 ·
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Originally Posted by Tagkaman View Post

I wouldn't worry. Most good psu's don't even get all that hot on their own anyway, and as long as you have a decent amount of airflow in your case, you'll have no problem at all.

Most top builders have their PSU facing inwards for looks, and none of them ever report problems.
It would serve the purpose of carrying some of the hot air generated by the GPU out of the case. It would be good for the GPU temperature and fan speeds, but obviously slightly worse for the PSU itself. But as long as it's not truly detrimental, I will try it. Thank you again.

As for seeing a lot of PSUs oriented with fans inside the case, I see that a lot. And lots of modern cases offer grille bottoms with dust filters for PSU air intakes, which is great. And yet I still see people orient their PSUs with fans facing up (when mounted at the bottom) even in those circumstances, which I also conclude is done for looks. I care for looks greatly--I like to mod my cases--but I also find it important to treat components properly, setting up a well-thought-out airflow plan, not frying components for looks, etc.
 

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Quote:
Originally Posted by Zero4549 View Post

Take a moment to remember than every single power supply ever was oriented with it's intake inside the chassis until a few years ago, and most still are, and you will have your answer.
What he said.
 

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Most PSUs come with great warranties anyway, so if it does fail due to heat (very unlikely), you can just RMA it.
smile.gif
 

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I'd say more than half of my systems still have the PSU pulling air from inside the case. In some cases, I think it's a benefit. In the past, they ALL were like that, and honestly going back to pre athlon-64 days, case airflow was terrible and most of the time the PSU was the only exhaust. It has never seemed to be a problem, but I think using good PSUs is part of that.
 

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Quote:
Originally Posted by ElevenEleven View Post

Additional question, having re-read the replies: what about PSUs that have fan curves assigned to PSU loads? And maybe the PSU fan won't even turn on until I draw 200 Watts--which can happen with my system while in some games. Such CPUs are meant to be cooled in a certain way when a certain amount of current is drawn to cool resulting generated heat. But if I don't draw enough current for how warm the PSU gets due to the additional heat from the GPU exhaust, it's still pretty safe? Basically only efficiency would suffer? I suppose that is why there are "hotbox" results for some PSU reviews.
2 things:

  • If your PSU is mounted at the bottom of your case, then it's not an issue since heat rises
  • The power draw on your PSU is not big enough to make the PSU warm enough for this to ever be a concern. You would have to have two 7970s that are heavily overclocked, heavily overvolted, and heavily loaded.
 

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Discussion Starter · #15 ·
Warm air rises in the absence of other forces. It's a gradual process of convection. Fans disrupt convection, and in a turbulent scenario of a small computer case, where there are 2 fans on a GPU tossing air all over the place, an intake fan or two at the front, etc., warm air will definitely not move peacefully and gradually upward. It will be a complex and dynamic environment, probably with a few deadzones and rapid mixing areas.
 

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Quote:
Originally Posted by ElevenEleven View Post

Warm air rises in the absence of other forces. It's a gradual process of convection. Fans disrupt convection, and in a turbulent scenario of a small computer case, where there are 2 fans on a GPU tossing air all over the place, an intake fan or two at the front, etc., warm air will definitely not move peacefully and gradually upward. It will be a complex and dynamic environment, probably with a few deadzones and rapid mixing areas.
Yeah, but still: the power consumption is barely even half of your PSU's total capacity. There's nothing to worry about here.
 

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Quote:
Originally Posted by ElevenEleven View Post

Thank you for taking your time to reply anyway
biggrin.gif
You're welcome.

So does this mean you're going to stop worrying about it?
 

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Originally Posted by ElevenEleven View Post

Yep! It's going to end up in a better set up for my GPU, so I'll swap the orientation soon.
Yeah, I'm with you: looks are important, so I enjoy being able to make things look nice when it's safe to do so.
 
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