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Old 11-25-2009, 11:51 AM   #1 (permalink)
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Default Heat/ Airflow/ PSU

Hi all.

I've seen some recent post(s) on this, and I also have a question.

Most of you are probably familiar with the Coolermaster 932 HAF case. The case is known for its airflow, and I have no major heat problems. But, if I can get my temps down a few degrees more.....hey, why not?

In another recent post I saw, something came up about PSU placement; it was this thread:

Airflow in my CM ATCS840

As you probably know, the 932 HAF offers mounting of the PSU either in the top or bottom of the case. When I put my build together, I thought I'd opt for the bottom because, at the time, it seemed convenient. Previous builds I've done in the past always seemed to have only one mounting space for PSU's: at the top.

Slaymate......if you're out there......I believe you mentioned in that other thread something very basic which never crossed my "feeble" mind at the time of my build: Heat rises.

I have a Corsair 750TX PSU. If I were to switch the placement of this PSU to the top of the case, I'd also have to swap out the top (roof) mounted 230mm fan that's there and put it at the bottom of the case, correct? And then position/ orient the fan so that it blows out the bottom of the case, right?

With that thing about "heat rises": I of course knew this all along But anyway, when I look at my PSU in the bottom of the case now, the 140mm fan is at the bottom. That fan's blowing downward, isn't it?

So if I were to switch the PSU to the top of the case, would I have to turn it up-side-down so that 140mm fan is facing the roof?

As my PSU is at the bottom of my case for the moment, when I look at it through the side window of the HAF case, I just see the "solid black" case. There's the open "grilled" part of the unit, but that's at the back of the HAF case facing out. And of course the 140mm fan is at the bottom of the case.

With the "heat rising" thing.......would there really be much heat escaping the PSU unit to rise up, travel over and across my other components?

Depending on the responses I get here, I want to make sure it's worth it to possibly go for a top-mounted PSU. It would be a bummer if I did this and saw no change in temps in either, say, my CPU or GPU temps. I'd like to see at least a few degrees of a drop if I were to do this. I'd have to rewire and re-route everything (not that that's a bad thing!!!!!).

Let me know what you think.

Thanks,
Pez
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Old 11-25-2009, 11:57 AM   #2 (permalink)
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Default Re: Heat/ Airflow/ PSU

I'm home on lunch so I'll read your post better later this afternoon. But the large fan on the power supply should be blowing down into the power supply with the air exiting out the back of the case. If the power supply fan is located at the bottom of the case make sure there is an opening in the case to allow air to get to the fan.
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Old 11-25-2009, 03:48 PM   #3 (permalink)
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Default Re: Heat/ Airflow/ PSU

the PSU fan on the bottom of your PSU pulls air into the psu, and it exits out the back(where the power cord plugs into). I haven't tested this, but I highly doubt you will notice any temp differences in cpu or gpu temps if you moved PSU to the top of a HAF 932. The amount of heat released by the PSU into the case is very minimal for how quickly the air in the case is replaced. I feel that you would have much better results by adding a 120mm bottom intake fan and/or a 120mm top exhaust fan(next to the big one, halfway into the top 5.25" drive bay).

With the PSU on the bottom of the HAF (which has a vent below the PSU) the PSU pulls cool air from outside the case (as opposed to warm air from inside the case with top mount placement). This in turn causes the PSU to operate at a lower temperature therefor releasing less heat. To install the fan in the top mount, you would have to take the top exhaust fan out, which does a great job at getting rid of the warm air inside the case. There are no mounting holes on the bottom of the case for the 230mm fan (you could always drill holes, but i'm not sure you want to do that).

Bottom mount design Pro's
-PSU runs cooler
-230mm top exhaust fan (and 120mm if you add one)
-120mm bottom intake (if you add one, no drilling needed)

Bottom mount Cons
-PSU releases some heat into case which must flow over components

I think to sum this up (This is my opinion, and conclusions have not been tested) If you are using the HAF 932 case you will see no benefit to moving the PSU unless it runs extreemly hot.

If you decide to move it to the top just to test, When you move the top 230mm fan to the bottom, you should have it pulling air into the case. bottom/front fans for intake, top/rear fans for exhaust is the general rule. Also depending on how big the PSU is, you could mount 1 or 2 120mm top exhaust fans which i would recommend as you would only have 1 140mm exhaust fan in the system.
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Old 11-25-2009, 06:25 PM   #4 (permalink)
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Default Re: Heat/ Airflow/ PSU

Well I don't have a HAF 932. But I have (2) i7 920 rigs and one has the Power Supply on the Top and one has the Power Supply on the Bottom.


I wanted a case with the Power Supply on Top because it gave me the room on the bottom for (2) GTX 280's in SLI with aftermarket coolers.



With the Power Supply on the Bottom there's only room for SLI with stock Coolers.



Here's a pic of what I started with.
You can see how close the Stock Card is to the Power Supply.



In these pictures you can see that the fans on the bottom card are occupying part of the space where the power supply would be. You should also note that I try a lot of different stuff





You can see how close the bottom pci-x slot is to the power supply in this pic.


You might also notice that I like posting pictures. But my point is the case with the Power Supply on Top, that also has (2) GTX 280's, runs cooler than the case with the Power Supply on the Bottom, that only has (1) GTX 280.

When it's all said and done, the only way for you to find out what works best for you is to try it both ways
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Old 11-25-2009, 08:25 PM   #5 (permalink)
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Default Re: Heat/ Airflow/ PSU

Slaymate... how did you mount the fans to the MB? I removed the stock black box piece of crap fan and can't seem to mount the fan to it. Zip ties don't hold around the bottom and it is really weird. What about double sided tape? I successfully mounted the fan on the VREG HS and it brought my temps down. Let me know if you have any creative ideas!

Edit: It's the 4th picture down... the fan showing there hooked up to the North Bridge HS... (is that the right term for it?)
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Old 11-25-2009, 09:29 PM   #6 (permalink)
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Default Re: Heat/ Airflow/ PSU

Yea, as i said, none of my advice was based on actual testing or anything like that, just theorizing. Another general rule would be listen to slaymate.
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Old 11-26-2009, 12:02 AM   #7 (permalink)
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Default Re: Heat/ Airflow/ PSU

Wow.....thanks for all the responses.

Slaymate: In one of your pics, I see you also have the Corsair 750TX

But let me ask this: In the pic that's fourth from the top, this is where you have the PSU mounted on the bottom, correct? And if I'm seeing things correctly, the PSU appears to be up-side-down; is this correct? I can see the fan of the PSU and it's facing the GTX 280 graphics card.

Did you originally do this deliberately?

Like I mentioned, as of this moment my PSU is on the bottom, but, the fan of the PSU is facing the bottom of the case, and the bottom of the case is vented (like a mesh grill, or, a net), so it has air. And as apsoul mentioned, the PSU fan pulls air into it and then pushes it out the back.

Since in that picture your PSU appears to be up-side-down, the fan is facing your graphics card; wouldn't the PSU fan be "pulling/ sucking" the air coming from the graphics card?

Am I asking too much or over-analyzing this? ;-)

Anyway......I might give this top mounting of my PSU a shot; I've got some time on my hands this long holiday weekend.

If I do it and my temps go down some degrees.....great! If they stay the same.....oh well, no harm, no foul. And it doesn't hurt to re-route the wires and get some nice, tight cable management!!

But if for some strange reason my temps go up - even a degree or two - then it's back to a bottom mount!!

Pez
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Old 11-26-2009, 10:45 AM   #8 (permalink)
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Default Re: Heat/ Airflow/ PSU

Quote:
Originally Posted by Guttzu View Post
Slaymate... how did you mount the fans to the MB? I removed the stock black box piece of crap fan and can't seem to mount the fan to it. Zip ties don't hold around the bottom and it is really weird. What about double sided tape? I successfully mounted the fan on the VREG HS and it brought my temps down. Let me know if you have any creative ideas!

Edit: It's the 4th picture down... the fan showing there hooked up to the North Bridge HS... (is that the right term for it?)
I just used zip-ties, the bottom 2 zip-ties ended up angling upwards until they were tight.

@ Pezzy

In that picture I did have the power supply flipped around. I'm not a fan of having my Power Supply act like a Vacumn Cleaner by sucking air into it from the carpet. There's a give and take to everything. The Corsair Power Supply is pointing down sucking air from the bottom, but that PC is at my Office which has a better carpet and it's cleaned a lot more often.

If your going to mount your power supply on the bottom of your case with the fan sucking from the bottom I highly recommend adding wheels or something to elevate the case away from the carpet/floor
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