Top Fan intake or exhaust?

[Noctua Fan Fan]

Hey guys,

 

An exhausted topic that we've seen plenty of videos about... where to put fans in a case!?

 

'm interested in some feedback on this config because I remember Luke mentioning in the video below that a top/front fan as an intake will help with thermals, but I don't see that it does help and I'm unsure on what to do. So instead I go to you, the community, to educate and prove me wrong on the question of top fan placements.

 

• Should there be 1 or 2?
• Should they both be intake, exhaust or 1 of each?

 

 

Setup Notes

Case is the CoolerMaster H500 (mesh front, not plastic).

All fans within are Noctua NF-A12x25 PWM fans except the front 200mm which are the stock CM 200mm case fans.

Radiator is for an AIO on the CPU. GPU is air cooled.

 

Diagram on current config:

 

I'm super interested in hearing people's opinions on what to do at the top of the case!

 

 

[Origami Cactus]

Hot air rises, turbulence is bad. There, now you have all the info you need. /s

 

Top fan should be exhaust in most cases, because of the 2 reasons i listed.

 

If you have top fan as intake, you risk making an air cycle, that just traps all the heat, and that is bad. 

[Noctua Fan Fan]

1 minute ago, Origami Cactus said:

Hot air rises, turbulence is bad. There, now you have all the info you need. /s

 

Top fan should be exhaust in most cases, because of the 2 reasons i listed.

 

If you have top fan as intake, you risk making an air cycle, that just traps all the heat, and that is bad. 

That's exactly what I thought. TOP and BACK as exhaust. But I have a friends who swear that the top with 2 fans should be exhaust above CPU and intake as front mounted for a case like this. I wanted to get another opinion because it made me doubt my instinct.

 

Also, thanks for commenting on another of my posts. You always offer great advice.

[narrdarr]

1 hour ago, A Gassy Gnome said:

 

have not done it personally. But putting a rad behind 200mm even with a push pull config goes against everything i know about airflow and cooling.

best config imho is:

2x 200mm front

rad on top as exhaust 2x 120mm in push( can do pull its easier to clean dust buildup)

rear can be intake or exhaust

        

 

Fyi:

air goes where you tell it to go. It does not matter if its hot or cool with one exception. That is convection cooling/ assisted convection cooling.

[HerrKaLeu]

Nice looking case!

 

Can you install the radiator on the top, exhausting? What you are doing now is cool the CPU (water-cooled) very well, but heat up the rest (inc. VRM, capacitors, RAM, grahics) with the warm air from the radiator. You also likely limit total air flow rate. IMHO one advantage of water cooling is that you can bring the heat outside the case. 

 

The top exhaust fan you show just removes some of the air from the radiator. 

 

If the front brings in more air than the Radiator exhausts (which should be possible to do silently with the 200 mm fans), the excess air will flow towards the back of the case and will exhaust through the holes by the PCI cards. so some more air goes over your Graphics. You may not even need the rear fan. To the contrary, with water cooled CPU you don't need to draw air up over the CPU, you want more to go over the graphics card. 

 

The large fans are high-flow / low pressure fans. The radiator fans are high pressure fans. So with he radiator behind the large fans, you kind of diminish them. Ultimately the overall cooling of ALL components will depend of ENTIRE case flowrate. 

[Noctua Fan Fan]

16 hours ago, HerrKaLeun said:

Nice looking case!

 

Can you install the radiator on the top, exhausting? What you are doing now is cool the CPU (water-cooled) very well, but heat up the rest (inc. VRM, capacitors, RAM, grahics) with the warm air from the radiator. You also likely limit total air flow rate. IMHO one advantage of water cooling is that you can bring the heat outside the case. 

 

The top exhaust fan you show just removes some of the air from the radiator. 

 

If the front brings in more air than the Radiator exhausts (which should be possible to do silently with the 200 mm fans), the excess air will flow towards the back of the case and will exhaust through the holes by the PCI cards. so some more air goes over your Graphics. You may not even need the rear fan. To the contrary, with water cooled CPU you don't need to draw air up over the CPU, you want more to go over the graphics card. 

 

The large fans are high-flow / low pressure fans. The radiator fans are high pressure fans. So with he radiator behind the large fans, you kind of diminish them. Ultimately the overall cooling of ALL components will depend of ENTIRE case flowrate. 

I originally had a blower style GPU (now a 2070S w/ 3 fans). And once I moved the rad to the front, the cooling for the GPU improved. I think because the CPU under real world load is hitting approx 40-50 max and the fans in front are more powerful and cooling the GPU so it was able to pass that heat off and draw in fresh air effectively.

 

However now I've swapped GPU, under real world load, is hitting 55 around its peak.

 

I am able to top mount the rad, but it does 'stick out' and doesn't look as clean.

 

I am able to swap the 2 x 200 on the front for 3 x 120mm fans. Aesthetically I'm not sure how good that would look and what gains I might get from temps.

 

[Noctua Fan Fan]

21 hours ago, narrdarr said:

have not done it personally. But putting a rad behind 200mm even with a push pull config goes against everything i know about airflow and cooling.

best config imho is:

2x 200mm front

rad on top as exhaust 2x 120mm in push( can do pull its easier to clean dust buildup)

rear can be intake or exhaust

        

 

Fyi:

air goes where you tell it to go. It does not matter if its hot or cool with one exception. That is convection cooling/ assisted convection cooling.

There's a bit of a space issue with the top mount. I don't like the look aesthetically either.

 

How would you feel if there were 3 x 120mm fans on the front, and 2x 120mm fans on the inside, with the rad in between in a more conventional push/pull?

[Demonic Donut]

Since you have an AIO, I would do top fan as exhaust. I doubt you'll get much improvement from doing 120s instead of the two 200s.  Spend the $50 or more on something else.

 

I dropped over 5C under GPU + CPU load when I put my top front fan to intake vs exhaust. But I have a D15, not an AIO. Hot GPU air was being pulled through the CPU cooler. Now it gets nice fresh air from the top front fan.

 

With air, its all about flow. Get the air changes as high as possible. Since you have two 200s plus 2 120s on the rad, two 120 exhausts should give relatively even static pressure. I wouldn't want to cause any increase in case static pressure by having another intake that isn't on the rad. It could cause your rad to be a little less effective. My general rule of thumb is # of Intakes Fans = # Exhaust fans + 1.

[narrdarr]

4 hours ago, A Gassy Gnome said:

I originally had a blower style GPU (now a 2070S w/ 3 fans). And once I moved the rad to the front, the cooling for the GPU improved. I think because the CPU under real world load is hitting approx 40-50 max and the fans in front are more powerful and cooling the GPU so it was able to pass that heat off and draw in fresh air effectively.

 

However now I've swapped GPU, under real world load, is hitting 55 around its peak.

 

I am able to top mount the rad, but it does 'stick out' and doesn't look as clean.

 

I am able to swap the 2 x 200 on the front for 3 x 120mm fans. Aesthetically I'm not sure how good that would look and what gains I might get from temps.

 

 

4 hours ago, A Gassy Gnome said:

There's a bit of a space issue with the top mount. I don't like the look aesthetically either.

 

How would you feel if there were 3 x 120mm fans on the front, and 2x 120mm fans on the inside, with the rad in between in a more conventional push/pull?

So, you don't really have temp issues....

99% of the time your always going to have trade offs that your going to need to balance

the 2  we are dealing with here are performance vs Aesthetics

 

I think everyone here would agree that the top mounted rad would be the best. But, the real question would be is how much better would it be?

Answer:  Well given your current temps maybe 5C better on the gpu and maybe i mean maybe a couple C worse for the cpu.

 

So, is that worth the trade off for the Aesthetics you want. From the sounds of it... No its not. Which is fine. With that in mind put 3x 120mm on the front will be better, but you will hate the way it looks. 

 

with everything on the table my recommendation would be to:

1. move the top fan from top front to top rear as exhaust. this will allow the air to travel through all the case.

2. (If it fits) add a 120mm fan below the rad as intake (if it doesn't fit no biggie)

 

 

 

[Fuzzyy]

On 7/11/2020 at 8:03 PM, A Gassy Gnome said:

Hey guys,

 

An exhausted topic that we've seen plenty of videos about... where to put fans in a case!?

 

'm interested in some feedback on this config because I remember Luke mentioning in the video below that a top/front fan as an intake will help with thermals, but I don't see that it does help and I'm unsure on what to do. So instead I go to you, the community, to educate and prove me wrong on the question of top fan placements.

 

• Should there be 1 or 2?
• Should they both be intake, exhaust or 1 of each?

 

 

Setup Notes

Case is the CoolerMaster H500 (mesh front, not plastic).

All fans within are Noctua NF-A12x25 PWM fans except the front 200mm which are the stock CM 200mm case fans.

Radiator is for an AIO on the CPU. GPU is air cooled.

 

Diagram on current config:

 

I'm super interested in hearing people's opinions on what to do at the top of the case!

 

 

If you have the space, which you probably do with that case, I prefer mounting the radiator on top as exhaust and having cool air coming from the front. It will lower the temps of your GPU because you won't be pushing the hot air from the radiator into the case. CPU temps won't change much, maybe it will increase 1-2C, but trust me, if you have the space on top, go for it. You will definently see the difference on your GPU. VRMS on the motherboard and RAM temperatures will drop too.

EDIT: I am rocking a Phanteks P400A and managed to squeeze a 240 rad on top, it is a very tight fit, but it significantly lowered the VRM temps on my GPU. CPU temps is also reduced for me since i am air cooling it and having 2 fans pulling the hot air out of it. Here is my setup and a picture:

Noctua NH-U12S for CPU

Kraken X52&G12 for GPU, AER120 fans exhausting got air from the case

3 NF-S12B fans on front as intake, 1 as exhaust

1 NF-P14 redux pushing air to cool the VRAM

[Noctua Fan Fan]

1 hour ago, narrdarr said:

 

So, you don't really have temp issues....

99% of the time your always going to have trade offs that your going to need to balance

the 2  we are dealing with here are performance vs Aesthetics

 

I think everyone here would agree that the top mounted rad would be the best. But, the real question would be is how much better would it be?

Answer:  Well given your current temps maybe 5C better on the gpu and maybe i mean maybe a couple C worse for the cpu.

 

So, is that worth the trade off for the Aesthetics you want. From the sounds of it... No its not. Which is fine. With that in mind put 3x 120mm on the front will be better, but you will hate the way it looks. 

 

with everything on the table my recommendation would be to:

1. move the top fan from top front to top rear as exhaust. this will allow the air to travel through all the case.

2. (If it fits) add a 120mm fan below the rad as intake (if it doesn't fit no biggie)

 

 

 

I appreciate your thoughts, time and effort here for this recommendation. I think I'll go for the change you've recommended.

 

Based on what @Fuzzyy has said I hadn't thought about RAM and VRM temps. But I think that the temperatures on everything in the current rad config is pretty good already. I don't really feel like the machine runs 'too hot' at any point.

 

I'm going to move the fan as recommended and leave the rest.

I CAN fit a 120 there, but not fixed to anything. I have tried previously. I think some case modding may be in store

[Noctua Fan Fan]

1 hour ago, Fuzzyy said:

If you have the space, which you probably do with that case, I prefer mounting the radiator on top as exhaust and having cool air coming from the front. It will lower the temps of your GPU because you won't be pushing the hot air from the radiator into the case. CPU temps won't change much, maybe it will increase 1-2C, but trust me, if you have the space on top, go for it. You will definently see the difference on your GPU. VRMS on the motherboard and RAM temperatures will drop too.

 

 

 

I could squeeze it on top, but aesthetically it encroaches onto the motherboard are and makes easily getting to the top headers/RAM etc. a bit annoying/impossible without removing while tinkering. So the front is probably best just for my general tinkering and the overall temps don't suffer that much so Im going to do what narrdarr suggested and move the fan from top front to top back

 

As you shared an awesome pic of yours, I thought I'd reciprocate:

 

 

[narrdarr]

9 hours ago, A Gassy Gnome said:

I appreciate your thoughts, time and effort here for this recommendation. I think I'll go for the change you've recommended.

 

Based on what @Fuzzyy has said I hadn't thought about RAM and VRM temps. But I think that the temperatures on everything in the current rad config is pretty good already. I don't really feel like the machine runs 'too hot' at any point.

 

I'm going to move the fan as recommended and leave the rest.

I CAN fit a 120 there, but not fixed to anything. I have tried previously. I think some case modding may be in store

Sounds good.

 

Fyi

cooling ram isn't that big of a deal they'll run fine regardless. VRM can handle more then people think but some air flow is worth it. have both fan in the back like this will make that happen.

 

no need to mod just get adhesive magnets to stick on the corners of the fan and let the magnet hold it there. But you can always mod if you want

[Noctua Fan Fan]

9 hours ago, narrdarr said:

Sounds good.

 

Fyi

cooling ram is that big of a deal they'll run fine regardless. VRM can handle more then people think but some air flow is worth it. have both fan in the back like this will make that happen.

 

no need to mod just get adhesive magnets to stick on the corners of the fan and let the magnet hold it there. But you can always mod if you want

I was thinking of adhesive magnets as a backup, but it might be the best idea full stop. I'll share what I end up doing

[Endyrtainment]

On 7/11/2020 at 1:03 PM, A Gassy Gnome said:

Hey guys,

 

An exhausted topic that we've seen plenty of videos about... where to put fans in a case!?

 

'm interested in some feedback on this config because I remember Luke mentioning in the video below that a top/front fan as an intake will help with thermals, but I don't see that it does help and I'm unsure on what to do. So instead I go to you, the community, to educate and prove me wrong on the question of top fan placements.

 

• Should there be 1 or 2?
• Should they both be intake, exhaust or 1 of each?

 

 

Setup Notes

Case is the CoolerMaster H500 (mesh front, not plastic).

All fans within are Noctua NF-A12x25 PWM fans except the front 200mm which are the stock CM 200mm case fans.

Radiator is for an AIO on the CPU. GPU is air cooled.

 

Diagram on current config:

 

I'm super interested in hearing people's opinions on what to do at the top of the case!

 

 

Pretty solid video review. Conceptually, I'm not sure I agree with placing the radiator on the intake compared to a top mount (Barring you have the option to do either).
By placing the radiator on the front you're reducing the total volume of airflow that runs through the system.
The question really becomes: Is the increased cooling received by the radiator large enough that it offsets the reduction of cool air intake for the total system?*

*Layman terms: A front mounted radiator will run cooler on the front intake comparatively to a top mounted radiator. The more optimized radiator temperature reductions results in the CPU temperature decrease by X%, and ultimately leads to less heat being contributed to the case by Y%. But, simultaneously this is also reducing the total amount of cool air that can flow through the case. While this air flow reduction isn't technically a temperature increase (Since no heat is being directly added to the system) it is a potential de-optimization of the system as a whole.

Below is my personal rig configuration. All of the stock case and radiator fans were replaced by 6 after market fans to optimize this configuration.
I think a great follow up video would be one that compares a front mounted radiator to a top mounted radiator with bonus points for taking into account specific Static Pressure (SP) and Air Flow (AF) optimization fans in their respective locations. Using a Static Pressure (SP) fan as your rear exhaust would just a de-optimization when compared to using an Air Flow (AF) fan - But by how much? Hopefully you'd tell us :D


P.S. This conversation is obviously dependent on your personal computer case and its limitations. If you cannot physically mount the radiator to the top of your case, then of course a front mounted radiator makes sense.

[Noctua Fan Fan]

4 hours ago, Endyrtainment said:

Pretty solid video review. Conceptually, I'm not sure I agree with placing the radiator on the intake compared to a top mount (Barring you have the option to do either).
By placing the radiator on the front you're reducing the total volume of airflow that runs through the system.
The question really becomes: Is the increased cooling received by the radiator large enough that it offsets the reduction of cool air intake for the total system?*

*Layman terms: A front mounted radiator will run cooler on the front intake comparatively to a top mounted radiator. The more optimized radiator temperature reductions results in the CPU temperature decrease by X%, and ultimately leads to less heat being contributed to the case by Y%. But, simultaneously this is also reducing the total amount of cool air that can flow through the case. While this air flow reduction isn't technically a temperature increase (Since no heat is being directly added to the system) it is a potential de-optimization of the system as a whole.

Below is my personal rig configuration. All of the stock case and radiator fans were replaced by 6 after market fans to optimize this configuration.
I think a great follow up video would be one that compares a front mounted radiator to a top mounted radiator with bonus points for taking into account specific Static Pressure (SP) and Air Flow (AF) optimization fans in their respective locations. Using a Static Pressure (SP) fan as your rear exhaust would just a de-optimization when compared to using an Air Flow (AF) fan - But by how much? Hopefully you'd tell us


P.S. This conversation is obviously dependent on your personal computer case and its limitations. If you cannot physically mount the radiator to the top of your case, then of course a front mounted radiator makes sense.

I love the amount of time you have spent on this quite old topic of mine and it provides wonderful insight to anyone going through to help them make a decision, and should I build in a similar case again its a valuable resource for me to come back and reference.

 

Since this post I have built in an O-11 Dynamic and will be finishing off the custom loop this upcoming weekend. So although I cannot put these lessons directly into practice in the short term, like I said, super valuable for me to come back to in the future.

 

Thank you!

[papareeves]

This is an old post but i had to give my two cents. I see a lot of the older builders think that a top mounted exhaust is best with an aio. Wrong It's been proven time and time again by multiple test (2jay,bitwit,gamingnexus) that front mount intake is best. I have the same case, set up in a push pull with the stock 200's and my 240rad. I noticed a 10 degree drop in cpu temps from front mounting as intake rather than top mounting exhaust, with a 0 degree difference in gpu, chipset, mos, or any other temps. Leave the top open with no fans, the air coming out of the aio is no more than a 2 degree difference than ambient air (even after a 2 hour stress) it is strong enough to blow straight to the back of the case. I've even taken out my rear exhaust fan and saw no difference in temps. The H500 is a very breathable case. I am however planning on switching the 2x 200's for 2 120 static pressure fans and 1 120 haf fan on the bottom to help with cpu temps as I've upgraded to a hotter cpu and need the extra rpm's to push threw the rad. If you notice a temp spike in your gpu temps I would suggest taking a 200 and placing it as a top mount exhaust and get rid of the rear exhaust to  help draw the air up rather than out  (if you have a open card).