Fans on bottom of a case question

[Yoshiii335]

Hello,

How well do bottom fans on a case cool off gpu's? I have a case I might put the 360 AIO on the front of the case and I am wondering if the bottom fans will be good enough to cool the 3090ti I have.

 

[Thimblewad]

Depends on from where they pull air and how hot it is. But in general → more fans = more airflow = lower temperatures. Of course, after a certain number, you get diminishing returns.

 

[dirtyferret]

Hello,

How well do bottom fans on a case cool off gpu's? I have a case I might put the 360 AIO on the front of the case and I am wondering if the bottom fans will be good enough to cool the 3090ti I have.

depends on the exact case, the exact gpu, and the rest of the set up. In some cases it can be counter productive. Are you having temp issues?

 

[AsRock]

People need more details about the case and setup you have.

I hope the AIO is not on the bottom of the case, water level drops you end up starving the pump.


We need more context.

 

[Kyan]

Depends on from where they pull air and how hot it is. But in general → more fans = more airflow = lower temperatures. Of course, after a certain number, you get diminishing returns.

I'm sure i've seen from gamer nexus and other that more fan is not equal to better airflow. It depends on lot of thing to improve the airflow

 

[doyll]

Hello,

How well do bottom fans on a case cool off gpu's? I have a case I might put the 360 AIO on the front of the case and I am wondering if the bottom fans will be good enough to cool the 3090ti I have.

Hard to say if bottom intakes will help or not. As aid, depends on case venting and bottom vent clearance, what fans are used, what GPU, etc.

If you have fan/s, try it and see what works best.

 

[eidairaman1]

Hello,

How well do bottom fans on a case cool off gpu's? I have a case I might put the 360 AIO on the front of the case and I am wondering if the bottom fans will be good enough to cool the 3090ti I have.

Cooler air sinks, warmer air rises, as long as you have 1+ inch gap you shouldnt have an issue

 

[dirtyferret]

Cooler air sinks, warmer air rises

yes, and slowly...otherwise the air goes in whatever direction my fan(s) send it

 

[Yoshiii335]

depends on the exact case, the exact gpu, and the rest of the set up. In some cases it can be counter productive. Are you having temp issues?

People need more details about the case and setup you have.

I hope the AIO is not on the bottom of the case, water level drops you end up starving the pump.


We need more context.

It’s a Fractal Meshify 2 case . I have a 3090ti EVGA FTW3, 7950x cpu. The AIO radiator and fan covers up the top of the motherboard vrm and part of the ram when top mounted.
I bought a Lian Li Lancool 3 case to replace and the AIO radiator and fan fits fine for top mount but I like the Fractal better and I think it’s built better.
I have to choose which case to use.

 

[claes]

LanCool 3 is a better performer overall and, with its vented bottom, will almost certainly provide better GPU cooling with bottom intakes. But, as you can see, the difference is minimal in their stock configurations. Given you have both on hand I’d just test both and see which you prefer.

 

[Nihillim]

You may need to clean the filter/grille down there more frequently, as dust settles around floors, desktops, etc.
Many cases that have bottom fan options don't seem to sit high enough for a significant benefit. Cooler Master SL600M did it right.
I took my O11 Evo and sat it on a pair of 2x4s...

 

[80251]

My case, an ancient, heavy, thermaltake Armor Revo has a place to put a single 120mm in the case floor. I tried high powered 92mm fans and a low power 120mm fan -- none of them seemed to make a difference in GPU temps.

 

[doyll]

Bottom vents work better with more space between bottom of case and floor. Normal bottom clearance is 20mm giving about half as much airflow area to bottom vent as bent has.

 

[claes]

Yeah; even with the lancool you’re unlikely to see any real benefit. You’d need bottom fans that actually attach to the bottom to overcome the resistance. Maybe you pull some air from the front-bottom intake that’d end up feeding the PSU, but not much.

 

[doyll]

Yeah; even with the lancool you’re unlikely to see any real benefit. You’d need bottom fans that actually attach to the bottom to overcome the resistance. Maybe you pull some air from the front-bottom intake that’d end up feeding the PSU, but not much.

Fan mounted push vs pull makes very little difference. Tested on radiators the temperature difference was 1.0-1.25c at 800rpm and even less at higher speed. Radiator is way more restrictive than case venting.

Taking what you posted literally, when you said "bottom fans that actually attach to the bottom" would put fans on outside of case meaning bottom of fans would be as low as bottom of case feet, maybe even lower as most feet are less than 25mm tall

Cooler air sinks, warmer air rises, as long as you have 1+ inch gap you shouldnt have an issue

Scientifically you are correct. It is what creates stack (chimney) effect in buildings and chimneys. But in computer cases even the very slightest external force (fan at lowest speed is many times needed effect) over-powers any air movement generated by air temp in our cases.

A good example of how little pressure our computer fans make, I calculated atmospheric pressure at 30 feet above sea level. There is a 11.013 mm H20 less pressure 30 feet above sea level than at sea leve.
Simple math shows that is 3.671 mm H2O less 10 feet above sea level than at sea level.
Or 1.863 mm H2O less 5 feet above sea level than at sea level.
That is about 1.836 mm H2O less pressure on our chest than on our feet.
The fans we use in our systems rarely have static pressure rating as high as 1.836 mm H2O .. and that is at full speed .. which most of us never use. At lower speeds their pressure differential is even less.

 

[eidairaman1]

Fan mounted push vs pull makes very little difference. Tested on radiators the temperature difference was 1.0-1.25c at 800rpm and even less at higher speed. Radiator is way more restrictive than case venting.

Taking what you posted literally, when you said "bottom fans that actually attach to the bottom" would put fans on outside of case meaning bottom of fans would be as low as bottom of case feet, maybe even lower as most feet are less than 25mm tall


Scientifically you are correct. It is what creates stack (chimney) effect in buildings and chimneys. But in computer cases even the very slightest external force (fan at lowest speed is many times needed effect) over-powers any air movement generated by air temp in our cases.

A good example of how little pressure our computer fans make, I calculated atmospheric pressure at 30 feet above sea level. There is a 11.013 mm H20 less pressure 30 feet above sea level than at sea leve.
Simple math shows that is 3.671 mm H2O less 10 feet above sea level than at sea level.
Or 1.863 mm H2O less 5 feet above sea level than at sea level.
That is about 1.836 mm H2O less pressure on our chest than on our feet.
The fans we use in our systems rarely have static pressure rating as high as 1.836 mm H2O .. and that is at full speed .. which most of us never use. At lower speeds their pressure differential is even less.

Yes I know but externally the cooler air is still at the bottom of the case hence why the bottom and front fan mounts are intake, notice how the aft and top fans are exhaust, it is basic physics.

But anyways My case I have 4 case fans, 2x 230s (intake and exhaust) and 2x140s (Intake and exhaust). I could Remove 1 of my Heatsink fans as the push/pull really isn't needed.

I could add 4 more 140s to the side panel but I would need another Rheostat/Potentiometer (I like manual control over my fans)

Fan mounted push vs pull makes very little difference. Tested on radiators the temperature difference was 1.0-1.25c at 800rpm and even less at higher speed. Radiator is way more restrictive than case venting.

Taking what you posted literally, when you said "bottom fans that actually attach to the bottom" would put fans on outside of case meaning bottom of fans would be as low as bottom of case feet, maybe even lower as most feet are less than 25mm tall


Scientifically you are correct. It is what creates stack (chimney) effect in buildings and chimneys. But in computer cases even the very slightest external force (fan at lowest speed is many times needed effect) over-powers any air movement generated by air temp in our cases.

A good example of how little pressure our computer fans make, I calculated atmospheric pressure at 30 feet above sea level. There is a 11.013 mm H20 less pressure 30 feet above sea level than at sea leve.
Simple math shows that is 3.671 mm H2O less 10 feet above sea level than at sea level.
Or 1.863 mm H2O less 5 feet above sea level than at sea level.
That is about 1.836 mm H2O less pressure on our chest than on our feet.
The fans we use in our systems rarely have static pressure rating as high as 1.836 mm H2O .. and that is at full speed .. which most of us never use. At lower speeds their pressure differential is even less.

Yes I know but externally the cooler air is still at the bottom of the case hence why the bottom and front fan mounts are intake, notice how the aft and top fans are exhaust, it is basic physics.

But anyways My case I have 4 case fans, 2x 230s (intake and exhaust) and 2x140s (Intake and exhaust). I could Remove 1 of my Heatsink fans as the push/pull really isn't needed.

I could add 4 more 140s to the side panel but I would need another Rheostat/Potentiometer (I like manual control over my fans)

 

[claes]

Fan mounted push vs pull makes very little difference. Tested on radiators the temperature difference was 1.0-1.25c at 800rpm and even less at higher speed. Radiator is way more restrictive than case venting.

Hey doyll, long time no see. I think you misread my post and or are unfamiliar with the chassis in question. The lancool 3 has “bottom” intakes that are attached to the PSU shroud and pull air from vents on either side of the PSU shroud. I was saying that it’s unlikely that they’ll pull much air from those vents.

Taking what you posted literally, when you said "bottom fans that actually attach to the bottom" would put fans on outside of case meaning bottom of fans would be as low as bottom of case feet, maybe even lower as most feet are less than 25mm tall

Come on, everyone knows what bottom intakes means. Pretty colloquial in this world. It’s not like you hear “top exhaust” and expect the fans to be external to the chassis. And, again, it’s the lancool 3 we’re talking about… no need to be abstract, OP owns two cases and is trying to decide which to keep. Read the thread? Your second post wasn’t even relevant to either chassis…

edit: my bad, forgot the meshify 2 has bottom intakes under the PSU shroud for some reason

 

[doyll]

Hey doyll, long time no see. I think you misread my post and or are unfamiliar with the chassis in question. The lancool 3 has “bottom” intakes that are attached to the PSU shroud and pull air from vents on either side of the PSU shroud. I was saying that it’s unlikely that they’ll pull much air from those vents.


Come on, everyone knows what bottom intakes means. Pretty colloquial in this world. It’s not like you hear “top exhaust” and expect the fans to be external to the chassis. And, again, it’s the lancool 3 we’re talking about… no need to be abstract, OP owns two cases and is trying to decide which to keep. Read the thread? Your second post wasn’t even relevant to either chassis…

edit: my bad, forgot the meshify 2 has bottom intakes under the PSU shroud for some reason

Yeah, I don't get around as much as I used to.
Hope all is going well for you and yours. Have a happy season!

I did not "misread" your post.
I just interpreted it differently than you intended it.

I did not know it was Lancool 3. Think it has 3x vents in PSU shroud and 3x vents plus 1x PSU vents for a total of 4x vents in bottom.
Not sure how well bottom intakes (mounted in PSU compartment) will perform. Lancool 3 feet are taller than most so that helps airflow to vents, but bottom fans would be restricted by not only bottom venting but also by PSU shroud venting. Fans would need quite high pressure rating.

Yoshiii335, keep in mind you need at least as many exhaust vents and you have intakes with fans.
Exhaust vents usually work quite well without fans

​

 

[claes]

Yeah, I don't get around as much as I used to.
Hope all is going well for you and yours. Have a happy season!

And you as well!

Not sure how well bottom intakes (mounted in PSU compartment) will perform. Lancool 3 feet are taller than most so that helps airflow to vents, but bottom fans would be restricted by not only bottom venting but also by PSU shroud venting. Fans would need quite high pressure rating.

It’s the meshify with the intakes inside the PSU shroud; the lancool has them atop the PSU shroud but has mesh sides to offer more air. But agreed, I don’t really believe either setup will help with GPU cooling much. Still worth a try yoshiii!

 

[doyll]

You first posted:

Come on, everyone knows what bottom intakes means. Pretty colloquial in this world. It’s not like you hear “top exhaust” and expect the fans to be external to the chassis. And, again, it’s the lancool 3 we’re talking about… no need to be abstract, OP owns two cases and is trying to decide which to keep. Read the thread? Your second post wasn’t even relevant to either chassis…

edit: my bad, forgot the meshify 2 has bottom intakes under the PSU shroud for some reason

I took the liberty of using bold on selected text in your post so there is no misunderstanding what you said.
"And, again, it’s the lancool 3 we’re talking about"
I took the liberty of using bold on selected text in your post so there is no misunderstanding what you said.
You clearly say case is "lancool 3" in above post.

When I answer you about Lancool 3 you post:

And you as well!

It’s the meshify with the intakes inside the PSU shroud; the lancool has them atop the PSU shroud but has mesh sides to offer more air. But agreed, I don’t really believe either setup will help with GPU cooling much. Still worth a try yoshiii!

Again, I took the liberty of using bold on seltected text in your post so there is no misunderstanding what you said.
"It’s the meshify with the intakes inside the PSU shroud"
So what case is it?

 

[claes]

Honestly don’t know why you’re arguing with me… Do you?

OP owns two cases and is trying to decide which is best. They prefer the meshify but wonder if the lancool iii would provide better GPU cooling.

The lancool iii has fan mounts atop the PSU shroud.

The meshify has fan mounts on the bottom of the chassis (inside the chassis, since you seem to be on one), under the PSU shroud.

In your post that I was responding to you incorrectly stated that lancool iii has fan mounts beneath the PSU shroud. I was just correcting you — it does not, and pulls air from the side intakes.

I think you need to reread the thread, revisit the product pages, or just have an eggnog and chill! Happy holidays!

 

[cvaldes]

The best person to answer this question is the original poster. After all, he has both cases (Fractal Meshify 2 and Lian Li Lancool III) in possession with the components he will be using.

Third-party product reviews can be useful at times although many case reviews are based on stock configuration -- with the factory included fans in their original location -- rather than a fully configured build with fans (including aftermarket units) in all mounting locations.

For sure the Lancool III does not include fans in the two mounts above the PSU shroud. Those must be added by the builder. In fact, these are generally the last pieces to be added to the build since they render the headers on the bottom of an ATX motherboard largely inaccessible.

Since the OP is using an AIO radiator, the placement of that will affect the overall airflow, not just location but also the fan performance.

I know nothing about the Fractal case but for sure the Lancool III's top accepts either 120mm or 140mm fans so the choice of fans there will affect thermal performance.

In summary, all the more reason why OP will arrive at the best answer by experimenting himself with the actual components he will be using in his build. He hasn't participated in this discussion since Monday so hopefully he made an effort to do this.

 

[doyll]

Honestly don’t know why you’re arguing with me… Do you?

OP owns two cases and is trying to decide which is best. They prefer the meshify but wonder if the lancool iii would provide better GPU cooling.

The lancool iii has fan mounts atop the PSU shroud.

The meshify has fan mounts on the bottom of the chassis (inside the chassis, since you seem to be on one), under the PSU shroud.

In your post that I was responding to you incorrectly stated that lancool iii has fan mounts beneath the PSU shroud. I was just correcting you — it does not, and pulls air from the side intakes.

I think you need to reread the thread, revisit the product pages, or just have an eggnog and chill! Happy holidays!

Honestly I find nothing in thread about OP having both cases until you posted it.

It's likely if you had been clear in your original post as well as later posted directed at me we would have had none of this conversation except for saying 'Hi" to each other.

Lancool III has fan mounts in PSU shroud, 3 of them. Fans can be mounted either on top or on bottom, although one mounted under shroud over PSU would have almost no air supply. Even mounted on top airflow would be limited to gap between PSU and shroud on front side

Guess I'm mistaken, I thought Lancool III had vents under HDD mounting trays. Sorry about that.

Moving on. Please have a good holiday season.

 

[Dirt Chip]

Bottom vents work better with more space between bottom of case and floor. Normal bottom clearance is 20mm giving about half as much airflow area to bottom vent as bent has.

I put my Define 7 on high heels, extra 25mm, for the bottom fan to breeze.
It`s a custom made 3d print (and sadly, green).
Not sure how much it help for the GPU, but the PSU also use that income air.
I think that the lowest front fan do the most for the GPU.

 

[doyll]

Maybe paint them black .. or wrap with black tape?

Bottom fans without extended feet flow air about the same as front fans. Distance from floor to bottom fans is similar to front front cover to fans.
Maybe experiment with and without front cover
Maybe try removing PCIe slot covers in back below GPU. This added rear vent area often improves front to back airflow moving heated air off of GPU on back and out.

What are your temps and fan speed now under heavy load?

I make castor bases like below for mine. Usually use 30mm castor but have also used 40mm. Depends on carpet.