Question Why doesn't my side intake fan reduce temps?

May 31, 2020
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I'm using a Phanteks 140mm static pressure fan in the side panel slot closer to the front of the case here:


The problem is, my GPU and CPU max and average temps are the same during stress tests, regardless of whether the side fan is running at min or max RPM.

Maybe it's mounted in a bad position? The fan isn't really blowing over the GPU, it's blowing right below it - but that's where the GPU intake fan (blower design) is drawing from, so I'd still expect GPU temps to be lower. Any ideas?
 

kanewolf

Titan
Moderator
I'm using a Phanteks 140mm static pressure fan in the side panel slot closer to the front of the case here:


The problem is, my GPU and CPU max and average temps are the same during stress tests, regardless of whether the side fan is running at min or max RPM.

Maybe it's mounted in a bad position? The fan isn't really blowing over the GPU, it's blowing right below it - but that's where the GPU intake fan (blower design) is drawing from, so I'd still expect GPU temps to be lower. Any ideas?
That is probably because there is no where for more input air to go. You need more exhaust to balance out the input.
 
May 31, 2020
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My only other fans are a front intake fan and a back exhaust fan, would I be running into that problem already? I figured a second intake fan right by the GPU would reduce temps by at least 2 or 3 degrees, instead of making no difference at all.
 

kanewolf

Titan
Moderator
My only other fans are a front intake fan and a back exhaust fan, would I be running into that problem already? I figured a second intake fan right by the GPU would reduce temps by at least 2 or 3 degrees, instead of making no difference at all.
The simple thing to do is to take the side panel off completely. If your temps don't change, then it isn't an airflow issue.
 

Gfost73

Prominent
Mar 23, 2019
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i came to fine the side fan is best as exhaust to pull heat from under the GPU. it never did nothing on my old case when i had it as intake, and did very little as exhaust but was better.
 

Gfost73

Prominent
Mar 23, 2019
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790
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also test the system, remove the side panel , does temps drop dramatically or at all? you wont get much better than 10-15°C above ambient temp with air cooling , Id try removing side, see how temps are, put side back on with fan off, see if its different, turn fan on , see if different, etc.. but as exhaust it would pull heat from GPU at least which will keep CPU cooler as that heat wont radiate towards top (where CPU normally are)
 
May 31, 2020
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I tried it with the side panel removed and GPU max/average temps (70-75 degrees) during stress testing were within 1 degree of side panel attached temps. It's a blower design GPU, so I don't think it's dumping much heat inside the case anyway. I feel like there's no way that the 2 fans included with my case already achieved optimal airflow before I added this third fan though.
 

Gfost73

Prominent
Mar 23, 2019
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790
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at stock my GPU will reach low 80s, I've adjusted my fan curve and undervolted the card, but also overclocked the core. I am able to keep my GPU under 80, but it often hits 70-72 during gaming. stress test the same as I play most games on Ultra its stressing my GPU most times.
 
May 31, 2020
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My GPU is undervolted and overclocked, I could push the OC much further but not without better cooling (hence the addition of a side intake fan). The GPU fan curve is already as loud as I can tolerate.
 

kanewolf

Titan
Moderator
I tried it with the side panel removed and GPU max/average temps (70-75 degrees) during stress testing were within 1 degree of side panel attached temps. It's a blower design GPU, so I don't think it's dumping much heat inside the case anyway. I feel like there's no way that the 2 fans included with my case already achieved optimal airflow before I added this third fan though.
Since your temps didn't change, it is not an airflow problem. 75c on a GPU is totally reasonable.
 
Reactions: Gfost73
May 31, 2020
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I understand that 75c is a reasonable GPU temp but that was achieved through limiting my overclock and setting a very loud GPU fan curve, both of which I'd rather not do. Is it really possible that the two cheap fans my case came with (140mm intake, 120mm exhaust) give the best attainable airflow?
 

Karadjgne

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Ambassador
Move the side panel fan to the top rear and block off both the side vents with cardboard and tape. Also block off the top-front vent.

You want the air to move through the case, to do that the exhausts need to create a vacuum in front of the fans. If you have big vents next to the fan, that's where the fan gets a lot of air from, not necessarily the case.

If you think of the pc as a hollow tube with a fan at each end, that's the idea you want. Front fan pushing air to be sucked in by the back fan. If you cut a hole in the tube near the rear fan, you'll not get much air moving from the front fan. The rear fan will pull fresh air from the hole.

So block off the big holes.
 

Karadjgne

Titan
Ambassador
Exhaust on top, exhaust at rear, intakes at front. Front fans push in cold air, top/rear fans push out hot air.

My old CM 690 II was great, it had the same 2x side panel fan slots, so I just flipped the sides. Put the side fan slots behind the motherboard side and a solid case side facing me. Your panels are square, might be able to simply swap them instead.
 

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