• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

For the 3 top fans, can I have 2 of them as outtake and 1 of them as intake?

Joined
Jan 3, 2021
Messages
32 (0.03/day)
Hi guys,

I can put 3 fans at the top of my case. I will call them: rear, mid, and front fans. I currently have the rear and mid installed as outtake fans.

I am planning to install the front fan, which is the fan that is closest to the front of the case. This fan has no heat generating components below it. It is also right next to the front intake fan. As such, if I set this fan as an outtake fan, wouldn't that fan be sucking the fresh air from the front intake fan, and immediately push it out of the case?

As such, I am planning to have this top fan as an intake fan instead. However, people tend to not use top fan as intake fan. So I was wondering whether this is okay to do?

Further, the remaining 2 top fans are outtake fan. In other words, I have three fans in a row. Two of which are blowing air out while one of which is blowing air in. Would this be a problem? For example, would the intake and outtake fan interfere with each other since they are blowing air towards two different directions?

Thanks a lot.

P.S. here's a video of my build. It might be easier for me to explain with the visual:
 
Joined
Nov 8, 2020
Messages
474 (0.38/day)
System Name Dusty
Processor 5900x
Motherboard MSI B550 Tomahawk
Cooling Noctua NH-D15
Memory Corsair Vengence LPX 32GB
Video Card(s) MSI RTX 3070 Gaming X
Storage yes
Case Fractal Design Define R6
Power Supply EVGA SuperNOVA 750w
VR HMD Oculus CV1
It's a fan, you can do whatever you wish with them. There is no right or wrong, or something that will explode or implode. It will just be better or worse. Best way to figure that out is to test it with your current case and build. When I had my AIO i tried mounting it in many places with fans going in or out to figure out what worked best in terms of temperature and noise. I ended up keeping in in the front as a intake.
 
Joined
Jan 3, 2021
Messages
32 (0.03/day)
It's a fan, you can do whatever you wish with them. There is no right or wrong, or something that will explode or implode. It will just be better or worse. Best way to figure that out is to test it with your current case and build. When I had my AIO i tried mounting it in many places with fans going in or out to figure out what worked best in terms of temperature and noise. I ended up keeping in in the front as a intake.
Thanks for replying. I'm not really worried about my aio fans/radiator location. I'm planning to install a third case fan on the top of my case, and I'm wondering whether having it as an intake fan would be problematic given: 1. it's a top fan and 2. two of my top fans are already outtake fans
 
Joined
Nov 8, 2020
Messages
474 (0.38/day)
System Name Dusty
Processor 5900x
Motherboard MSI B550 Tomahawk
Cooling Noctua NH-D15
Memory Corsair Vengence LPX 32GB
Video Card(s) MSI RTX 3070 Gaming X
Storage yes
Case Fractal Design Define R6
Power Supply EVGA SuperNOVA 750w
VR HMD Oculus CV1
I know, I was giving an example if you re-read it again.
 
Joined
Nov 25, 2019
Messages
793 (0.50/day)
Location
Taiwan
Processor i5-9600K
Motherboard Gigabyte Z390 Gaming X
Cooling Scythe Mugen 5S
Memory Micron Ballistix Sports LT 3000 8G*4
Video Card(s) EVGA 3070 XC3 Ultra Gaming
Storage Adata SX6000 Pro 512G, Kingston A2000 1T
Display(s) Gigabyte M32Q
Case Antec DF700 Flux
Audio Device(s) Edifier C3X
Power Supply Super Flower Leadex Gold 650W
Mouse Razer Basilisk V2
Keyboard Ducky ONE 2 Horizon
I'm expecting the airflow to be a mess, otherwise no problems with that. You could really just test it yourself as it isn't something hard.
 

64K

Joined
Mar 13, 2014
Messages
6,104 (1.66/day)
Processor i7 7700k
Motherboard MSI Z270 SLI Plus
Cooling CM Hyper 212 EVO
Memory 2 x 8 GB Corsair Vengeance
Video Card(s) MSI RTX 2070 Super
Storage Samsung 850 EVO 250 GB and WD Black 4TB
Display(s) Dell 27 inch 1440p 144 Hz
Case Corsair Obsidian 750D Airflow Edition
Audio Device(s) Onboard
Power Supply EVGA SuperNova 850 W Gold
Mouse Logitech G502
Keyboard Logitech G105
Software Windows 10
Youve got 3 intake fans on the front. I would just make the 3 top fans outtake fans. It seems to me if you put 1 intake fan on the top the 2 outtake fans would just pull the air from that intake fan right out and it wouldn't do much good.
 
Joined
Jan 3, 2021
Messages
32 (0.03/day)
Youve got 3 intake fans on the front. I would just make the 3 top fans outtake fans. It seems to me if you put 1 intake fan on the top the 2 outtake fans would just pull the air from that intake fan right out and it wouldn't do much good.
Ya that makes sense. The top fan that I will install will be right next to the front intake fans though. Wouldn't it be pulling the front intake fan's fresh air right out of the case?
 
Joined
Aug 14, 2013
Messages
2,373 (0.61/day)
System Name boomer--->zoomer not your typical millenial build
Processor i5-760 @ 3.8ghz + turbo ~goes wayyyyyyyyy fast cuz turboooooz~
Motherboard P55-GD80 ~best motherboard ever designed~
Cooling NH-D15 ~double stack thot twerk all day~
Memory 16GB Crucial Ballistix LP ~memory gone AWOL~
Video Card(s) MSI GTX 970 ~*~GOLDEN EDITION~*~ RAWRRRRRR
Storage 500GB Samsung 850 Evo (OS X, *nix), 128GB Samsung 840 Pro (W10 Pro), 1TB SpinPoint F3 ~best in class
Display(s) ASUS VW246H ~best 24" you've seen *FULL HD* *1O80PP* *SLAPS*~
Case FT02-W ~the W stands for white but it's brushed aluminum except for the disgusting ODD bays; *cries*
Audio Device(s) A LOT
Power Supply 850W EVGA SuperNova G2 ~hot fire like champagne~
Mouse CM Spawn ~cmcz R c00l seth mcfarlane darawss~
Keyboard CM QF Rapid - Browns ~fastrrr kees for fstr teens~
Software integrated into the chassis
Benchmark Scores 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
There’s a chance it’ll recirculate the hot air blowing out from the middle-top fan. As @64K noted and you pointed out, you’re not actually cooling anything with an intake there.

Do you need another fan? Are any of your components running hotter than you’d like?

If it were me, I’d mount the radiator to the top and run all top fans as exhaust, whether it’s two or three. This way your GPU should run a little cooler as it won’t be taking in the radiator’s heat.

Or, if mounting the radiator on front is preferred, I’d actually just run the front and top as intakes. Hopefully that setup would create a cooler case temperature and thus cooler air for the GPU to work with.

edit: IMHO, that’s too many fans for such a small chassis.
 

64K

Joined
Mar 13, 2014
Messages
6,104 (1.66/day)
Processor i7 7700k
Motherboard MSI Z270 SLI Plus
Cooling CM Hyper 212 EVO
Memory 2 x 8 GB Corsair Vengeance
Video Card(s) MSI RTX 2070 Super
Storage Samsung 850 EVO 250 GB and WD Black 4TB
Display(s) Dell 27 inch 1440p 144 Hz
Case Corsair Obsidian 750D Airflow Edition
Audio Device(s) Onboard
Power Supply EVGA SuperNova 850 W Gold
Mouse Logitech G502
Keyboard Logitech G105
Software Windows 10
Ya that makes sense. The top fan that I will install will be right next to the front intake fans though. Wouldn't it be pulling the front intake fan's fresh air right out of the case?

Do you have any cutouts on the bottom of the case? If so you could move the intake fans to the bottom of the case.
 
Joined
Jan 3, 2021
Messages
32 (0.03/day)
There’s a chance it’ll recirculate the hot air blowing out from the middle-top fan. As @64K noted and you pointed out, you’re not actually cooling anything with an intake there.

Do you need another fan? Are any of your components running hotter than you’d like?

If it were me, I’d mount the radiator to the top and run all top fans as exhaust, whether it’s two or three. This way your GPU should run a little cooler as it won’t be taking in the radiator’s heat.

Or, if mounting the radiator on front is preferred, I’d actually just run the front and top as intakes. Hopefully that setup would create a cooler case temperature and thus cooler air for the GPU to work with.

edit: IMHO, that’s too many fans for such a small chassis.
Oh this is interesting. So if I were to keep the radiator at the front, your suggestion is to have the top three fans and front three radiator fans as intakes? This would mean 6 intake fans and 1 outtake fans (at the back). Is that what you meant?

Do you have any cutouts on the bottom of the case? If so you could move the intake fans to the bottom of the case.
Unfortunately the max number of fans for my case is 7, with 3 at the front, 3 on top, and one at the back
 
Joined
Jun 3, 2010
Messages
2,540 (0.50/day)
If you do that you will turn your case into a vacuum cleaner. You prioritise intake for this reason - so that air doesn't slip in through the cutouts.
 
Joined
Jan 3, 2021
Messages
32 (0.03/day)
If you do that you will turn your case into a vacuum cleaner. You prioritise intake for this reason - so that air doesn't slip in through the cutouts.
Ya I agree. Positive air pressure inside the case is optimal. Would you suggest I use the top fan as intake then? (Front 3 are already intake. Back 1 is outtake. So I only have top 3 to work with. There aren’t any other outputs in the case)
 
Joined
Aug 14, 2013
Messages
2,373 (0.61/day)
System Name boomer--->zoomer not your typical millenial build
Processor i5-760 @ 3.8ghz + turbo ~goes wayyyyyyyyy fast cuz turboooooz~
Motherboard P55-GD80 ~best motherboard ever designed~
Cooling NH-D15 ~double stack thot twerk all day~
Memory 16GB Crucial Ballistix LP ~memory gone AWOL~
Video Card(s) MSI GTX 970 ~*~GOLDEN EDITION~*~ RAWRRRRRR
Storage 500GB Samsung 850 Evo (OS X, *nix), 128GB Samsung 840 Pro (W10 Pro), 1TB SpinPoint F3 ~best in class
Display(s) ASUS VW246H ~best 24" you've seen *FULL HD* *1O80PP* *SLAPS*~
Case FT02-W ~the W stands for white but it's brushed aluminum except for the disgusting ODD bays; *cries*
Audio Device(s) A LOT
Power Supply 850W EVGA SuperNova G2 ~hot fire like champagne~
Mouse CM Spawn ~cmcz R c00l seth mcfarlane darawss~
Keyboard CM QF Rapid - Browns ~fastrrr kees for fstr teens~
Software integrated into the chassis
Benchmark Scores 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
If you’re trying to fill all of the slots, all intake except rear exhaust is probably your best choice if the radiator is in front.

Still, that’s a silly amount of fans IMO. Is there a problem component that’s overheating?
 
Joined
Jun 3, 2010
Messages
2,540 (0.50/day)
Ya I agree. Positive air pressure inside the case is optimal. Would you suggest I use the top fan as intake then? (Front 3 are already intake. Back 1 is outtake. So I only have top 3 to work with. There aren’t any other outputs in the case)
You know what, switch the direction of every fan. Front - exhaust, rear - intake.
You are running liquid cooling, it would be best for your radiator fans to take the cooler case air than let the hub heat up and there is no other cooling alternative for your vrms. Vrms have to have fresh, cool air.
 
Joined
Jan 14, 2019
Messages
9,725 (5.12/day)
Location
Midlands, UK
System Name Nebulon-B Mk. 4
Processor AMD Ryzen 7 7800X3D
Motherboard MSi PRO B650M-A WiFi
Cooling be quiet! Dark Rock 4
Memory 2x 24 GB Corsair Vengeance EXPO DDR5-6000
Video Card(s) Sapphire Pulse Radeon RX 7800 XT
Storage 2 TB Corsair MP600 GS, 2 TB Corsair MP600 R2, 4 + 8 TB Seagate Barracuda 3.5"
Display(s) Dell S3422DWG, 7" Waveshare touchscreen
Case Kolink Citadel Mesh black
Power Supply Seasonic Prime GX-750
Mouse Logitech MX Master 2S
Keyboard Logitech G413 SE
Software Windows 10 Pro
Benchmark Scores Cinebench R23 single-core: 1,800, multi-core: 18,000. Superposition 1080p Extreme: 9,900.
You can, but it doesn't mean you should. Heat naturally rises, so with an intake on the top, you're only obstructing its way. Besides, an intake fan right next to an exhaust has a chance of pulling already exhausted hot air back into the case. Not recommended.
 
Joined
Jun 3, 2010
Messages
2,540 (0.50/day)
You can, but it doesn't mean you should. Heat naturally rises, so with an intake on the top, you're only obstructing its way.
That is liquid cooling, nothing is rising there. The heat is at the front radiator.
 
Joined
Jan 14, 2019
Messages
9,725 (5.12/day)
Location
Midlands, UK
System Name Nebulon-B Mk. 4
Processor AMD Ryzen 7 7800X3D
Motherboard MSi PRO B650M-A WiFi
Cooling be quiet! Dark Rock 4
Memory 2x 24 GB Corsair Vengeance EXPO DDR5-6000
Video Card(s) Sapphire Pulse Radeon RX 7800 XT
Storage 2 TB Corsair MP600 GS, 2 TB Corsair MP600 R2, 4 + 8 TB Seagate Barracuda 3.5"
Display(s) Dell S3422DWG, 7" Waveshare touchscreen
Case Kolink Citadel Mesh black
Power Supply Seasonic Prime GX-750
Mouse Logitech MX Master 2S
Keyboard Logitech G413 SE
Software Windows 10 Pro
Benchmark Scores Cinebench R23 single-core: 1,800, multi-core: 18,000. Superposition 1080p Extreme: 9,900.
That is liquid cooling, nothing is rising there. The heat is at the front radiator.
Sorry, my bad. In that case, I'd suggest installing the radiator on the top, and using its fans as exhaust in order to trap as little hot air inside the case as possible.

Also, an intake fan on the top, right next to a front radiator that also acts as intake is counterproductive in removing heat from the radiator. The top should be exhaust in any case.
 
Joined
Jun 3, 2010
Messages
2,540 (0.50/day)
In that case, I'd suggest installing the radiator on the top, and using its fans as exhaust in order to trap as little hot air inside the case as possible.
I agree, no reason to restrict the air intake. While it could still work, cool air has higher impedance. Good radiator fans are not available to everyone. It would be easier to push it through the radiator in heated state and with the fans out of the way of the hot radiator stream.
 
Last edited:
Top