[SOLVED] What would be the best fan setup?

Sep 14, 2020
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My case has 2 x 120mm fans, one for intake and one for exhaust, both rated at ~54 cfm. I am looking to improve ventilation.

Which of these scenarios would be best:
  1. Add 3 120mm fans. Intake: 3 x 120 mm front (~162 cfm) Exhaust: 1 x 120 mm rear, 1 x 120 mm top rear (~108 cfm). Net CFM +54 cfm
  2. Add 2 140 mm fans. Intake: 2 x 140 mm front (164 cfm) Exhaust: 1 x 120 mm rear, 1 x 120 mm top rear (108 cfm). Net CFM +56
  3. Add 4 120 mm fans. Intake: 3 x 120 mm front, 1 x 120 mm top mid (216 cfm) Exhaust: 1 x 120 mm rear, 1 x 120 mm to rear. (108 cfm). Net CFM +108 CFM
  4. Add 2 120mm fans. 2 front, 2 rear. Net CFM 0.

I am looking for the best performance/noise.

For any other suggestions fan configuration for me case is as follows:
Front: 3 x 120 mm OR 2 x 140 mm
Top: 2 x 120 mm OR 2 x 140 mm
Rear: 1 x 120 mm
 
Solution
A)If you plan to stick with the Wraith Prism cooler - be aware, that the power of the 3080 gpu may prove to be too much for the Prism cooler to deal with; some of the card's heat WILL be fed into that cooler.
Front intake: 2x 140mm or 3x 120mm
Top exhaust: 2x 140mm or 2x 120mm
Rear exhaust: 1x 120mm

B)If you plan to change to a cpu tower air cooler
Front intake: same as option A
Top exhaust: This one is a bit of a pick your poison deal. 2x top exhaust will lead to slightly lower gpu thermals with non-blower designs, but slightly higher cpu thermals. Single fan won't change much if a rear exhaust is already present.
Rear exhaust: Depends on the specs of the fan being placed there VS the one(s) on the cpu cooler. If it is weaker, it will...

Phaaze88

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I can aid with the performance end, but not noise, because it's actually subjective, believe it or not.
1)I don't see a chassis model.

2)I don't know what the fans in question are.

3)I don't know what any of the hardware is, or what kind of coolers they're using.

No one can really answer this without SOME information. What works best is not universal... or you could just make it really simple and stick to the front to back setup.
 
Sep 14, 2020
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Thanks for your reply. I can provide all that.

1. Case model is the Phanteks p400 with additional front panel mesh.

2. Stock fans are Phanteks PH-F120S.
Additional fans I am considering are:
120 mm: Noctua NF-F12 PWM
140 mm: Noctua NF-A14 PWM

3. Hardware would be:
AMD 3700x with stock Wraith Prism cooler
Nvidia 3080 series GPU
80+ gold 850w PSU
Aorus Pro B550

Would be used to run games at max settings.
 
Last edited:

Phaaze88

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A)If you plan to stick with the Wraith Prism cooler - be aware, that the power of the 3080 gpu may prove to be too much for the Prism cooler to deal with; some of the card's heat WILL be fed into that cooler.
Front intake: 2x 140mm or 3x 120mm
Top exhaust: 2x 140mm or 2x 120mm
Rear exhaust: 1x 120mm

B)If you plan to change to a cpu tower air cooler
Front intake: same as option A
Top exhaust: This one is a bit of a pick your poison deal. 2x top exhaust will lead to slightly lower gpu thermals with non-blower designs, but slightly higher cpu thermals. Single fan won't change much if a rear exhaust is already present.
Rear exhaust: Depends on the specs of the fan being placed there VS the one(s) on the cpu cooler. If it is weaker, it will just get in the way and won't be needed at all.

C)If you plan to use a hybrid cooler instead, it changes even more, depending on the size and position, though the P400 only supports front and back positions.
 
Solution
Sep 14, 2020
3
0
10
A)If you plan to stick with the Wraith Prism cooler - be aware, that the power of the 3080 gpu may prove to be too much for the Prism cooler to deal with; some of the card's heat WILL be fed into that cooler.
Front intake: 2x 140mm or 3x 120mm
Top exhaust: 2x 140mm or 2x 120mm
Rear exhaust: 1x 120mm
I know this is the case with the FE versions, but is this also true for the AIBs? I plan on getting an EVGA release which has 3 fans... Not sure if any of those are exhaust fans though. I see for this case you used negative pressure... Is this because of the extra heat toward the CPU from the GPU?

B)If you plan to change to a cpu tower air cooler
Front intake: same as option A
Top exhaust: This one is a bit of a pick your poison deal. 2x top exhaust will lead to slightly lower gpu thermals with non-blower designs, but slightly higher cpu thermals. Single fan won't change much if a rear exhaust is already present.
Rear exhaust: Depends on the specs of the fan being placed there VS the one(s) on the cpu cooler. If it is weaker, it will just get in the way and won't be needed at all.

Eventually I plan on changing the CPU cooler.. But at the moment am sticking with the stock cooler. No plans on hybrid cooling.
 

Phaaze88

Titan
Ambassador
I know this is the case with the FE versions, but is this also true for the AIBs? I plan on getting an EVGA release which has 3 fans... Not sure if any of those are exhaust fans though. I see for this case you used negative pressure... Is this because of the extra heat toward the CPU from the GPU?
AIB, FE gpu models aside:
-Axial fan cooled models - basically most non blower models - dump most of their waste heat inside the chassis, some of which inevitably gets pulled into cpu coolers - except for the front mounted hybrid coolers.
They cool better than blower and are typically quieter too. The downsides have been their larger sizes and airflow; these models don't cool as well in close proximity to solid surfaces.

-Blower fan models push their heat directly out the back and do not interfere with cpu cooling, but are loud.
They do excel in cooling in tight spaces over the axial coolers. It's why Quadro and Firepro cards exclusively use blowers; the people who actually need them are going to stack multiple gpus together in a PC.

-Hybrid cooled models can go either way compare to the previous 2.

The EVGA model you describe is axial fan. The fans draw air into the heatsink, and the heat is spread out in all directions from the sides of the card.
Better for gpu cooling, but it does so while screwing over cpu cooling a little.

That's not necessarily negative pressure, but it has to do with how the top-down area coolers function.
The fan draws air from above it, pushes it down into the heatsink, and that heat spreads out in all directions. TDA coolers would do better with a side intake over it, but with how trendy windows have been, those are almost completely phased out on modern chassis.
So instead, the TDA cooler is 'cooling' on mostly gpu exhaust.

Nvidia's new cooler design may prove to be more efficient than axial fan designs - half the card moves the heat right outside the chassis and the other half is inside... reviews should shed some light on how well it does, though.
 
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I know this is the case with the FE versions, but is this also true for the AIBs? I plan on getting an EVGA release which has 3 fans... Not sure if any of those are exhaust fans though. I see for this case you used negative pressure... Is this because of the extra heat toward the CPU from the GPU?
Most of the designs from board partners regarding the GeForce 30 series have a similar "through-airflow" concept that NVIDIA is doing with their FE card either by having a shorter PCB than the entire length of the thing or poking holes in it. None of the board partner cards that I've seen have a direct exhaust channel however. So it's still dumping all of the heat back into the case, but some of it can go right through the card.

While I hope that reviewers will do CPU temperature readings with the GeForce 30 cards with through-airflow designs to get some data, I'm not convinced that any air that gets through will significantly increase the heat load of the CPU to the point there'll be issues. If anything, M.2 SSDs are a good candidate to look at. I've had one where it was installed on the backside of the motherboard in an Mini-ITX case where the backside got a lot of waste heat from the GPU. I had another where it sat basically next to the video card. Both were bare most of the time and they rarely exceeded 65C or had issues.

As long as you have good airflow going across both the video card and CPU heat sink, I don't see much reason for concern. The more of that hot air you can get out in a given amount of time, the better.
 
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