Noctua Airflow Guide

McCarthy

McCarthy

McCarthy

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Anyone tried the 3x front intake, 2x top ( intake at the front 1 exhaust at the back), then one rear exhaust? Seems to be the best way to do it, it makes sense!


faqs.noctua.at

Airflow Guide - Next Steps

This article is the second instalment of the airflow guide, giving more in-depth considerations for achieving optimal airflow. It covers the correct choice of fans, other components, the number of fans and more information on case pressure. P...
faqs.noctua.at faqs.noctua.at
 
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McCarthy said:
My temps at the minute are good, just wondering if this would make any worthwhile difference?
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From my past experience playing with this kind of setup, I had found that it works better if you have "ducting" to divert the exhaust and the intake at the top of your case to facing different directions; this would help limit the amount of recycling of the exhausted air back into the case to increase efficiency (by not pulling as much hotter air back into the case to cool with and help baffle any noise coming from the fans and vents a little).

So for example, I cut an OCUK box in half that was part of a delivery to fit the top of my Corsair 650D and stick some foam into the inside of the box halves that now sit on top of the case. I angle the box halve at the rear to exhaust outwards towards the back of the case (where the rest of the case is exhausting and venting out warm air anyway), and angle the front box halve towards the back panel of the case, so it is drawing in air from an entirely different direction to where any warmer air from the PC might be lingering.

It looks terrible and janky, but helped reduce some of the temps on the CPU.

However, as in the video and on the FAQ, it highly depends on what you've got in your case (how hard you're running it, overclocked, power use, etc), as well as possibly some other minor details on stuff exterior to the case (so for example, the ducting I talked about above to help this, would become even more noticeable in effiecy if the case was under a desk at a corner of a room, as all the hot air that's trapped is not being recycled in as much because the intake there and at the front of the case is cooler air from somewhere else).
 
McCarthy said:
2x top ( intake at the front 1 exhaust at the back),
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Makes far more sense than having them both as exhaust (which seemed to be a common thing), as having the front top fan as exhaust just sucks all the cool air out again before it's had a chance to reach any components.

However just completely blanking off the front top fan (i.e. and just have one top fan at the rear - as exhaust) is probably just as effective, as it prevents the "recycling" of warm air as @Meddling-Monk mentions.
 
I have 3 x Noctua 140mm front intake fans, 1 x 140mm exhaust for cpu, 2 x 140mm top exhaust (added one since pic taken) for gpu hot air.

My case is a Bequiet which has been inverted so window on right.


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Glanza said:
Plenty of people on the Noctua subreddit run their setup like this in various cases, some it works better than others.
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Right, because for best airflow it really depends on your individual setup. Everything down to the exact placement/hole pattern of the fan holes, CPU/GPU heatsink size/shape, open/closed PCI slot covers etc and a bunch more seemingly trivial things will affect your results.
 
I run a similar setup to this guide after reading it a while back, can’t really see anyone talking about it after I did a google search ages ago when doing it.

Running 2x140 front intake, 1x120 mm bottom intake (NZXT H5 Flow), 1x120mm top intake positioned in front of CPU air cooler, 1x120mm top exhaust positioned behind CPU air cooler and 1x120 mm exhaust rear of case.

Seems to run well but haven’t made any comparisons yet by swapping things around but does seem to make sense in my head.
 
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As stated, having exhaust and case intake fans side by side creates a circular airflow.
Airflow is caused by a difference in pressure between two locations; air moves from areas of higher pressure to areas of lower pressure.
Fans move air the same way; they have higher pressure on exhaust side than on intake side, see below example:

LL

Hope that helps

Airflow is a tricky beast often flowing differently than we think it will. Everything in our cases causes turbulence including fans. Turbulence causes air to move in all directions instead of flowing straight. Also, fans don't blow air straight thru a case. They usually move air in a cone shape .. sometimes directly away from fan sides.
 
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I think it’s interesting that there was no mention of fan speed and how setting different speeds on different fans inside the case will also have an impact.

It’s kind of warm here at the minute so I might give this a go when I get time. I’m using the Fractal Design North XL Mesh. This case also came with a bracket that fits to the inside, side of the case wherever you can install two extra fans and position the bracket up or down in the case wherever you like. I’ve never used them but I’m thinking maybe getting more air directly to a part of the case might also be worth a go, they’re free after all.
 
McCarthy said:
I think it’s interesting that there was no mention of fan speed and how setting different speeds on different fans inside the case will also have an impact.

It’s kind of warm here at the minute so I might give this a go when I get time. I’m using the Fractal Design North XL Mesh. This case also came with a bracket that fits to the inside, side of the case wherever you can install two extra fans and position the bracket up or down in the case wherever you like. I’ve never used them but I’m thinking maybe getting more air directly to a part of the case might also be worth a go, they’re free after all.
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Using the same case here. I was able to use a vertical GPU and side intake, great for GPU, slightly worse for the PCH and NVME. Far from throttling but few Celsius worse. Back to horizontal GPU, side intake and GPU temperature within margin of error from vertical setup but much better temperature for PCH and NVME.
PS: for the horizontal setup, depending on the GPU, a 90 degree cable is a must.
 
Drumroll said:
Using the same case here. I was able to use a vertical GPU and side intake, great for GPU, slightly worse for the PCH and NVME. Far from throttling but few Celsius worse. Back to horizontal GPU, side intake and GPU temperature within margin of error from vertical setup but much better temperature for PCH and NVME.
PS: for the horizontal setup, depending on the GPU, a 90 degree cable is a must.
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I was finding one of my NVME drives was a little warmer also . I’m using a 5090. Like you say it’s well within acceptable but my previous case and previous GPU were a little cooler. To be expected I suppose.

Great case I find. I had the Lian Li 011xl previously and found I was forever cleaning the glass lol.
 
I've seen a few videos over the years comparing fan configs but the problem is it's case specific and also changes depending on if you air cool or liquid cool.

But generally speaking, for most people it looks like strong positive pressure works best - that means have no more than a single 120mm or 140mm extracting air and have all other fans as intake and if you have lots of fans run the intake fans at the front and bottom of the case, leave the top of the case empty

As mentioned by others, having a decent distance between your intake and extract fans is key, that's why for most people a single 120mm at the back extracting is enough, any further extract fans are likely to sit too close to the intake fans and create a negative loop for no benefit.
 
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I have two intakes in the front that pass over the HDs and an exhaust at the back for the CPU. I have an exhaust on the top that does the whole box with the GPU mounted as close to it as poss.

When not under load the front two pass more into the box than the exhausts creating positive pressure. Under load just throws heat out of the back and top.

By far the best arrangement I've found.
 
Grim5 said:
I've seen a few videos over the years comparing fan configs but the problem is it's case specific and also changes depending on if you air cool or liquid cool.

But generally speaking, for most people it looks like strong positive pressure works best - that means have no more than a single 120mm or 140mm extracting air and have all other fans as intake and if you have lots of fans run the intake fans at the front and bottom of the case, leave the top of the case empty

As mentioned by others, having a decent distance between your intake and extract fans is key, that's why for most people a single 120mm at the back extracting is enough, any further extract fans are likely to sit too close to the intake fans and create a negative loop for no benefit.
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Yeah there are variables to consider such as the radiator for your AIO if using one. I’ve always thought that top exhaust is the way to go for this and never had any temp issues doing it this way, but maybe there is a better way when taking the info provided into account?
 
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