Fan configuration with NH-D15 G2

HankSc0rpi0 · Sunday at 20:24

See pic of my setup

New photo · Thursday, Aug 28

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Noctua have said in their blog that for Fractal North with NH-D15 that cooling was best with Top front fan set to intake and Top rear top set to exhaust

Which fan setup works best in the Fractal Design North?

Designed in Austria, Noctua's premium cooling components are renowned for their superb quietness, exceptional performance and thoroughgoing quality.

noctua.at

Just wonder if something similar would apply to Flux Pro. I have my top rear set to exhaust and was thinking of adding 2 more NF-A14x25 G2 fans to top as intake.
I don't mind if it doesn't improve cooling as long as it doesn't increase temps. It's more of an aesthetic thing.

Anyway, worth a shot ?

Glanza · 2025-09-08T08:46:50+0100

With that setup and case you've got currently can't see it making a difference, it works well on the North as that's a smaller case and has a different front panel.

HankSc0rpi0 · 2025-09-08T12:06:07+0100

Thanks, I had a feeling it would be a waste all right. Not sure if it would mess with air flow also. I've asked Noctua. lol.

doyll · 2025-09-08T12:24:43+0100

HankSc0rpi0 said:
See pic of my setup

New photo · Thursday, Aug 28

Tap to view!

photos.app.goo.gl

Noctua have said in their blog that for Fractal North with NH-D15 that cooling was best with Top front fan set to intake and Top rear top set to exhaust

Which fan setup works best in the Fractal Design North?

Designed in Austria, Noctua's premium cooling components are renowned for their superb quietness, exceptional performance and thoroughgoing quality.

noctua.at

Just wonder if something similar would apply to Flux Pro. I have my top rear set to exhaust and was thinking of adding 2 more NF-A14x25 G2 fans to top as intake.
I don't mind if it doesn't improve cooling as long as it doesn't increase temps. It's more of an aesthetic thing.

Anyway, worth a shot ?

I wouldn't add more fans. You already have 6x intake fans pushing air into case with 2x exhaust fans, 2x top vents and 1x rear fan with significant rear venting as well. That's 5x intakes supplying cool air to CPU cooler's 1 fan (2x fans stacked flow same amount of air) and GPU's 2-3x smaller fans in GPU. That's way more case airflow than components need. That's good because the extra intake case airflow helps move heated exhaust air on thru and out of case. A case can only flow as much air in as is flowing through and out of it. Case vents without fans still flow lots of air out of case. Also the less turns air makes going thru case means less turbulence which means smoother airflow and that means more airflow. More fans in top would blow into airflow from front fans creating massive turbulence in airflow going to CPU cooler, or pull cool intake air up and out before it reaches CPU cooler. As it is now only front bottom and bottom front fans are flowing into each other .. not a real problem. If you add more fan in top, test with them running and unplugged and see what your temps are. My guess is not running will be best.

My builds usually have front full of intake fans and maybe a bottom intake. All holes not covered by these intakes in front and bottom are sealed so air fan push into case has to flow on thru case to get out, not leak thru holes into lower pressure area in front of intake fans so air goes in circles not thru case. I like 1.5-2 times as much intake fan area as component cooler fan area. Your system is fine as is so adding more running fans would likely make system noisier as well.

I use a cheap digital indoor/outdoor thermometer with wired remote sensor to monitor air temp in front of cooler intake fans to make sure air temp entering coolers is no more than a couple degrees warmer than air entering case. Can use terrarium, fridge, etc remote sensor thermometers instead.
Link below is to basic guide to case airflow and how I monitor air temperature:

* * Ways to Better Cooling; Airflow, Cooler & Fan...

Got tired of posting instructions and guides over and over and over, so decided to start a thread for them. Please do not post unnecessarily as it will make it harder for others to find what they are looking for. This thread is not for opinions of the data or tutorials. If you have questions...

www.overclock.net

HankSc0rpi0 · 2025-09-08T12:28:16+0100

Thanks for the advice @doyll Much appreciated

doyll · 2025-09-08T12:42:40+0100

HankSc0rpi0 said:
Thanks for the advice @doyll Much appreciated

No problem. Thanks for saying above. Any questions fell free to ask.

HankSc0rpi0 · 2025-09-08T12:49:18+0100

@doyll I forgot to mention that Noctua advised me to put a fan in the basement too. You can't see it from the attached pic, but it's blowing air directly towards the psu shroud fans. Noctua support said it made a difference in their testing of the upcoming Noctua x Antec case. I added it anyway and it does seem to help keep overall noise down. I can almost never hear any of the case fans when gaming or benching, ever. I suppose I have a very soft fan curve but it's rare anything ever hits 750rpm. PSU fan never comes on and the GPU fans are extremely quiet under load with zero coil whine. I guess I got lucky and should leave things as they are.

doyll · 2025-09-08T13:28:56+0100

HankSc0rpi0 said:
@doyll I forgot to mention that Noctua advised me to put a fan in the basement too. You can't see it from the attached pic, but it's blowing air directly towards the psu shroud fans. Noctua support said it made a difference in their testing of the upcoming Noctua x Antec case. I added it anyway and it does seem to help keep overall noise down. I can almost never hear any of the case fans when gaming or benching, ever. I suppose I have a very soft fan curve but it's rare anything ever hits 750rpm. PSU fan never comes on and the GPU fans are extremely quiet under load with zero coil whine. I guess I got lucky and should leave things as they are.

Fans in basement would help. Seal all openings not covered by intake fans in bottom and front as said above. Computer fans are really weak fans. Airflow is created by higher pressure areas of air flowing into lower pressure areas. Fans generate lower pressure area on intake side and higher pressure area on exhaust side.

Computer fans are very weak and make very little pressure. Very few make 1.836mm H2O static pressure. (Static pressure is how much pressure a fan push into a sealed container are full speed). The difference in pressure standing at sea level with toes in ocean and pressure on our chest/neck 5 feet above sea level is 1.836mm H2O.
I determined above by starting with the difference in barometric pressure at sea level and 30 feet above sea level is 11.013 mm H20. That means the difference between sea level and 10 feet above sea level of 3.671 mm H2O, which is 1.836mm H2O between sea level and 5 feet above sea level.
That is 1.836 mm H2O less pressure on chest than on our feet when they are touching ocean.

Case grills (holes punched into sheet metal) disrupt airflow considerably. Depending on pattern / hole size they block airflow and create turbulence lowering airflow 30-70%. Best grill is ones made of round wire in rings.

Lots more I could say. You might find link below is to thread I did years ago with lots of different guides helpful. First post has list of topics with post number, but many of it's links don't open post number, so just find their post number in thread.

* * Ways to Better Cooling; Airflow, Cooler & Fan...

Got tired of posting instructions and guides over and over and over, so decided to start a thread for them. Please do not post unnecessarily as it will make it harder for others to find what they are looking for. This thread is not for opinions of the data or tutorials. If you have questions...

www.overclock.net