[SOLVED] placing case fans intake/exhaust how to achieve the best cooling

w1418826

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Mar 25, 2015
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so, my case is a phanteks p400s I should be able to have three fans in the front two on top and one in the back. with the 240mm radiator in the front as intake I wasn't able to fit another intake in the front, I am not sure exactly why but there just wasnt room. so right now my fans are set up as:

2 intake in the front attached to the radiator
1 on the back as exhaust
1 top, back as intake (bad idea I am sure)
1 top, front as exhaust

I wanted three intakes hence the one I put on the top but my gpu is warming up more than I would like and am wondering if this fan set up is making it worse. If anyone could suggest a better setup with the space available, I know positive air pressure is normally the way to go..

For reference the gpu is a evga rtx 2080 super xc ultra, it hit 77 degrees which I know isn't too bad but it was slowly increasing the longer I played games so it would most likely have gone higher. The ambient room temp was slightly above 26 degrees Celsius
 
Solution
so, my case is a phanteks p400s I should be able to have three fans in the front two on top and one in the back. with the 240mm radiator in the front as intake I wasn't able to fit another intake in the front, I am not sure exactly why but there just wasnt room. so right now my fans are set up as:

2 intake in the front attached to the radiator
1 on the back as exhaust
1 top, back as intake (bad idea I am sure)
1 top, front as exhaust

I wanted three intakes hence the one I put on the top but my gpu is warming up more than I would like and am wondering if this fan set up is making it worse. If anyone could suggest a better setup with the space available, I know positive air pressure is normally the way to go..

For reference the gpu...
so, my case is a phanteks p400s I should be able to have three fans in the front two on top and one in the back. with the 240mm radiator in the front as intake I wasn't able to fit another intake in the front, I am not sure exactly why but there just wasnt room. so right now my fans are set up as:

2 intake in the front attached to the radiator
1 on the back as exhaust
1 top, back as intake (bad idea I am sure)
1 top, front as exhaust

I wanted three intakes hence the one I put on the top but my gpu is warming up more than I would like and am wondering if this fan set up is making it worse. If anyone could suggest a better setup with the space available, I know positive air pressure is normally the way to go..

For reference the gpu is a evga rtx 2080 super xc ultra, it hit 77 degrees which I know isn't too bad but it was slowly increasing the longer I played games so it would most likely have gone higher. The ambient room temp was slightly above 26 degrees Celsius

Top two exhaust
Top Rear Exhaust
Front two intake.

Balanced air pressure is the way to go. Under pressurizing starves it of air. Over pressurizing leads to stagnant air spots. Balanced leads to the most moving air. But if you can't get balanced, a little over pressurized is better. High pressure air is usually denser air @ given temperature. That makes heat exchange surfaces more efficient.

If you are using the same model fans, you could cut back the exhaust fan speed by 1/3rd (66% front instake RPM) and have a balanced flow. But this is only a rough estimate because the radiator slows things down a bit. Without the proper anemometers and pressure gauges it's near impossible to tell what a proper balance is.
 
Solution

Eximo

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If you are going to have another intake, the best to use would be the rear and have the two top as exhaust. I do that myself to get cool air across my motherboard VRMs since the front is water cooled like in your situation. Though my top exhaust is also a radiator, so I also want cool air fed directly into it.

Having two fans opposing each other in close proximity is kind of bad.
 

w1418826

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Mar 25, 2015
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If you are going to have another intake, the best to use would be the rear and have the two top as exhaust. I do that myself to get cool air across my motherboard VRMs since the front is water cooled like in your situation. Though my top exhaust is also a radiator, so I also want cool air fed directly into it.

Having two fans opposing each other in close proximity is kind of bad.


hmm, interesting I never considered this, I suppose that makes sense considering heat rising and all that.. does that negatively effect the flow of the air coming from the front? I know it seems the majority of the warm air goes out the back as of now, but the fan I use in the back has higher rpm so it would be a good intake.. your thermals are solid though I am assuming?
 

Eximo

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Well, as digitalgriffin pointed out, there are always factors.

You can try both out though. In your situation I don't think it will make a huge difference in terms of temperatures. Though with too much exhaust you might create a negative pressure system. This would suck air into the case through any tiny gaps and make cleaning tedious. With excess intake, you create a positive pressure system. This should keep dust out of the system, but may negatively impact cooling.


I did it in my case because I have two 280mm radiators. Front intake, push/pull, and top exhaust. I was a tad worried about the motherboard VRMs since they are not water cooled, so I wanted air going over them. And I assumed the top radiator would suck in a lot of that cool outside air. Kind of like having two radiators as intake.

I have more surface area then I need to cool my system. I am running my CPU ragged at 5Ghz with a huge voltage, and it is still kept under control. All my intakes are filtered, so it has been relatively dust free since I built it. Wipe down the GPU backplate and chassis basement every few months and shake out the filters.
 

w1418826

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Mar 25, 2015
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yea I feel this would be simple if I could just get that 3rd fan onto the front then I could have those 3 and one exhaust on top, one in the rear.. The radiator wont move up anymore though because there is a small board right above it where things plug into for the cases ports (or lights?) at the top of the case.

Anyways, it seems like having the rear fan as intake and both top fans as exhaust has to be better than the current setup, yes? I know the glass right in front of the gpu gets very warm so I don't know if that indicates a stagnant air spot.. my 2 gpu cables are directly in front of one of the intake radiator fans too, so there is that heh.

I know I must be over thinking this by now..
 

w1418826

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Mar 25, 2015
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update:
so I was able to maneuver another intake fan onto the front, it was a pain but its there. now have 3 intakes in the front, one exhaust in the back and two exhaust on top.

also was able to route the vga cables out of the way and set a fan curve for the gpu so my idle temps on the gpu have dropped almost 10 degrees and in game havent seen it go above 70 degrees. much better, thank you guys