AIO cooler and airflow questions in a restricted case

[Morgan MLGman]

Hello everyone,

 

I wanted to ask a few questions about how should I put the fans on my AIO. I hope our cooling gurus can help me

I've got a Phanteks P400 case with a tempered glass panel - this case only allows AIOs larger than 120mm to be placed in the front.
This case isn't good in terms of airflow, fresh air comes in only through the front (picture for reference, intakes marked with arrows):

Exhaust: On the top of the case, there are two Phanteks PH-F140SP fans and in the back, there's one Noctua NF-F12 Chromax on the 120mm GPU radiator.

The 240mm Corsair H100i V2 blocks some of the air coming in, making the case a hot oven (it's the reason why I switched from a hot GPU like a 980Ti to a Hybrid 1080 card).
The fans are in a push configuration with the radiator on the inside of the case, and the fans under the front panel.:


Right now, the AIO has stock Corsair fans which have pretty decent cooling capabilities but are too loud at reasonable RPM so I ordered two Corsair ML120 PRO fans to replace them.

With the background set, I wanted to ask a few questions based on what you can see above:
1. Are the Corsair ML120 PROs good-enough for a radiator with such restricted airflow?

2. Does the fan placement (inside of the case or under the front panel) matter in terms of cooling capabilities? If so, which way? Under the front panel, there's less space but on the other hand the inside of the case is less crowdy that way.
3. When the two ML120 PROs arrive, should I put them in push or pull for better cooling & silence? This question is caused by this review: https://www.vortez.net/articles_pages/corsair_ml_pro_series_review.html
stating that:

Quote

Again, the eight ML140 fans averaged more than 60 CFM through a tight rad. More: when the fans were put in pull position, and air was measured as it entered the box, the eight fans averaged 72.8 CFM. That is, a user will gain 10 CFM by turning these fans over from push to pull. Something to think about.

 

4. With the ML's installed (regardless in which way), should I still use the two stock fans to make it a Push/Pull config? Would that help the CPU temps and/or the case airflow in general? Or would it only interfere with ML120 PROs and their excellent performance due to the fact that the stock fans are worse and have different specifications?

5. Would reversing the airflow be worth it in this case? I mean - to use top & rear fans as intakes and the 240mm AIO as the exhaust, or is it not worth even considering?
6. Any other ideas to improve the general airflow in my particular setup knowing all the mounted fans, or is this the best I could do with a 240mm AIO in the front?

When I had to RMA my H100i V2, I temporarily put a single 120mm AF fan in the front, and my old 980Ti temps improved by quite a lot with just a single 120mm intake fan instead of a 240mm rad with two 120mm fans - this is why I assume that the airflow issue is caused by the AIO due to the case design. I will not change it to an aircooler, because of aesthetic reasons though.

Thanks very much to anyone willing to respond, I appreciate it.
Cheers, Morgan

 

 

 

[Dschijn]

1. yes, but not if you want a super quiet setup. Best 120mm fans right now would be the new NF-A12x25

2. kind of. If you want better GPU temperatures you should make the back fan as intake. Two fans in the top + one in the back as exhaust will most certainly create negativ air pressure in the case (too much out and not enough intake).

3. shouldn't matter. But worth a try regarding that review

4. I would only push/pull the same fans. With mixed fans you will risk to even worsen the temperatures if the specs are too far off.

5. Best CPU and GPU temps: both rads as intake and top exhaust

6. my point 5 and maybe consider makeing the rads in push/pull

[meenmeen1103]

I think previous temps with the 980ti can be ignored, since the 120mm rad on the hybrid takes care of the bulk of the GPU heat, exhausting it straight out of the case.

 

As far as best temps with your new hardware, I theorize that simply setting up both fans and the rad inside the case would make more of a difference than either push or pull configs alone, as doing so makes the air flow straighter from the intakes on the front panel into the fan blades. The added elevation of the fans themselves in their current position makes the air flow in more of a 'S' like pattern, can be changed to a imitate just two 90deg turns instead. Might also be worth it to block all the cutouts surrounding the fans on the front of the case, underneath the front panel, to mitigate re-circulating hot air from inside the case and create a better vacuum to draw cool air from the top and bottom vents on the front panel.

 

The new fans I would assume mainly would help reduce noise without much performance change if at all.

[Morgan MLGman]

Thank you very much for your responses! The ML120 Pros arrived earlier today and they reduced noise a bit with pretty much the same performance - still, the goal of buying them was achieved.
 

7 hours ago, Dschijn said:

1. yes, but not if you want a super quiet setup. Best 120mm fans right now would be the new NF-A12x25

2. kind of. If you want better GPU temperatures you should make the back fan as intake. Two fans in the top + one in the back as exhaust will most certainly create negativ air pressure in the case (too much out and not enough intake).

3. shouldn't matter. But worth a try regarding that review

4. I would only push/pull the same fans. With mixed fans you will risk to even worsen the temperatures if the specs are too far off.

5. Best CPU and GPU temps: both rads as intake and top exhaust

6. my point 5 and maybe consider makeing the rads in push/pull

Though the NF-A12x12 aren't designed for radiators in terms of static pressure so wouldn't the NF-F12s be better? I thought they were the best so I bought one to slap on the 120mm rad on my GPU...
As for the rear intake, I will definitely give it a shot! Would just reversing the NF-F12 Chromax work? I mean, using it as a pull one for the 120mm rad? Is a pull-only setup pretty much equal to a push one?
 

7 hours ago, meenmeen1103 said:

I think previous temps with the 980ti can be ignored, since the 120mm rad on the hybrid takes care of the bulk of the GPU heat, exhausting it straight out of the case.

 

I agree, I mentioned it only to show the difference when there's no radiator in the front of the case

7 hours ago, meenmeen1103 said:

As far as best temps with your new hardware, I theorize that simply setting up both fans and the rad inside the case would make more of a difference than either push or pull configs alone, as doing so makes the air flow straighter from the intakes on the front panel into the fan blades. The added elevation of the fans themselves in their current position makes the air flow in more of a 'S' like pattern, can be changed to a imitate just two 90deg turns instead. Might also be worth it to block all the cutouts surrounding the fans on the front of the case, underneath the front panel, to mitigate re-circulating hot air from inside the case and create a better vacuum to draw cool air from the top and bottom vents on the front panel.

2

Alright, so things to do: Reversing the rear radiator fan to make it another intake, and moving the front radiator fans as pull ones inside of the case. I only don't understand the boldened part in the quote above, can you elaborate on that?

Thanks!

[Dschijn]

The NF-A12x25 are a allrounder fan. From my measurements they perform worse than the NF-F12 at the same rpm, yes.

BUT

They are much quieter than the NF-F12 and cool better at the same noise level. So we need to start thinking outside of the box and completly focus on performance to noise ratio!

 

I made a graph from my measurments (on a 360 HW Labs GTS).

 

[Marinatall_Ironside]

1 hour ago, Dschijn said:

The NF-A12x25 are a allrounder fan. From my measurements they perform worse than the NF-F12 at the same rpm, yes.

BUT

They are much quieter than the NF-F12 and cool better at the same noise level. So we need to start thinking outside of the box and completly focus on performance to noise ratio!

 

I made a graph from my measurments (on a 360 HE Labs GTS).

 

-snip-

What testing equipment were you using to get your results?

 

For my configuration (a custom water loop yes), I base my fan curves on the coolant temperature, since logically and practically, the radiator cools the coolant running through it, so it makes sense going this route. I have Corsair ML120 2-pack fans (since each fan in a 2-pack is cheaper than the ML Pro line, so better bang-for-the-buck)

 

@Morgan MLGman the best way to go about it would be to simply run the fans faster to compensate for the restricted front panel. Doesn't really matter if the fans are set up in push or pull with the case your system it's in. You can also experiment with having top and rear fans set up as intake and make the front exhaust.

[Dschijn]

HW Labs 360 GTS radiator

8700k@5GHz (just 4 Threads Prime95 load)

GTX 1080Ti@2GHz (load with Furmark)

temperatures measured with a water and a ambient air sensor conencted to a Aquaero 6 Lt

noise measured with an iPhone 8 at 40mm distance to the fan on the suction side with the app "Schall App"

 

Especially the noise measurement is not perfect, but its the only device I got for that. Overall it meets my personal impression of the fan so it can't be that wrong

 

The Corsair ML are definitely worth it, but don't fit my taste of ultra silent for idle and low rpm.

 

[meenmeen1103]

4 hours ago, Morgan MLGman said:

I agree, I mentioned it only to show the difference when there's no radiator in the front of the case

Alright, so things to do: Reversing the rear radiator fan to make it another intake, and moving the front radiator fans as pull ones inside of the case. I only don't understand the boldened part in the quote above, can you elaborate on that?

With these cutouts being between the pathway of the fans (mounted either as shown or on the inside of that same panel) and intake vents, they leave potential for hot air from within the case to recirculate back in. Just a minor possible variable.

Also, not sure if it's worth setting the rear GPU rad as intake for the positive air pressure benefit, I would think having the hot air exhausted straight out of the case would be better for under load situations. Could try both ways, wouldn't be too much hassle.

[WoodenMarker]

A dense rad and restrictive front means a bad time for fans at low rpm. If it fits, moving the 240mm rad to the top for exhaust with the ML's and using the Phanteks fans for front intake might be better. 

A SP120L push and ML120 pull on the rad should perform well but it might not fit with the rad at the top. 

[Neokolzia]

To whoever said above making rear fan intake, don't do this.

 

Its important to have linear airflow in a case else your forcing your fans to work alot harder to overcome pressure inside the case or against various air currents.

So facing two fans effectively against each other is very counter productive.

 

Push pull can help but your best bet is to either just take front panel off, or mod it to have more breathing,  Dremel/add vents etc.

Alot of new cases have terrible airflow/temps because of this new design fad of flat front panels with little slits to breaths.

 

I get a 8C difference in my dual 420mm custom loop if I close my front door, its that bad.

[Morgan MLGman]

12 hours ago, WoodenMarker said:

A dense rad and restrictive front means a bad time for fans at low rpm. If it fits, moving the 240mm rad to the top for exhaust with the ML's and using the Phanteks fans for front intake might be better.

It's sadly not possible to fit the 240mm rad at the top of the case in a P400   There's not enough clearance between the top of the case and the motherboard (especially with pretty beefy VRM cooling such as my Maximus VIII)...

12 hours ago, WoodenMarker said:

A SP120L push and ML120 pull on the rad should perform well but it might not fit with the rad at the top. 

So using the stock fans as push and the new ML's as pull would work well? Wouldn't they interfere with each other due to different specs? Honestly, I don't want to spend that much money for another pair of MLs

1 hour ago, Neokolzia said:

Push pull can help but your best bet is to either just take front panel off, or mod it to have more breathing,  Dremel/add vents etc.

Alot of new cases have terrible airflow/temps because of this new design fad of flat front panels with little slits to breaths.

Sadly, modding the case is not an option - I like how it looks and I don't want to ruin it. I'm not feeling confident enough to do mods like that I'm just looking to get the best-case scenario for airflow with my current setup.

[WoodenMarker]

6 hours ago, Morgan MLGman said:

So using the stock fans as push and the new ML's as pull would work well? Wouldn't they interfere with each other due to different specs? Honestly, I don't want to spend that much money for another pair of MLs

They should work fine if the fans are running at a similar rpm. Linus has an old video testing with SP120 and AF120's for push / pull which seemed to perform better than using the same fans together.

 

[nhguapo]

To the original poster, I'm kind of the same boat as you and would like to know what you've discovered.  I have a 280mm radiator up front and a ftw3 hybrid gpu that gets quite toasty while set to exhaust.  I'm curious what you ended up doing.  The gpu radiator fan as an intake sounds like a good idea.

[Morgan MLGman]

3 hours ago, nhguapo said:

To the original poster, I'm kind of the same boat as you and would like to know what you've discovered.  I have a 280mm radiator up front and a ftw3 hybrid gpu that gets quite toasty while set to exhaust.  I'm curious what you ended up doing.  The gpu radiator fan as an intake sounds like a good idea.

I can help you if you're having airflow issues with your P400 but you need to either need to create a new thread or use direct message, "reviving" old threads is not allowed so I'll close this thread - I'll contact you via PM.