Why is the Noctua NH-D15 so damn good?

Hardware Cooling
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I have had this cooler for years and build Intel and AMD rigs with it, and it just keeps on going. For air cooling, what could be better than this cooler?

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I have a theory

Some aliens came to earth and gave Noctua some Colling secrets.
I have bought an used NH-D14 with no fans.
Even with some cheap low speed Arctic F12 the cooler is insanely good.
On the other hand there are quite a few fans, that are better than Noctua for lower price. But the air coolers?
Man, forget the D15.
U12S is outperforming a lot of 140mm coolers and even some dual fan dual towers.
U12S is probably the best 120mm cooler there is.
People talk about the CM Hyper212, but the U12S is massively outperforming it


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It’s overall size, between contact/cold plate and amount of metal involved
has it still being viable - even with likes of desktop CPUs creeping on to 300(+)W
Once all CPUs venture on, closer to credit card for scale, then the 15s days are done

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The D15 cooler itself is a good performer, but the stock fans suck on the chromax model and are even worse on the original. You have to message Noctua cust. support, but they’ll send you three sets of 140mm fans clips upon request. The best performing fans on the market in terms of CFM and static pressure are (IMO) the Noctua A14 iPPC 3000s @160CFM. The D15 performs extremely well under 250W sustained loads, but struggles when you start to go north of 280W. The thermal performance also starts to stagnate when the fans push past ~2300RPM. I love the D15, but I would not use it on a high TDP Ryzen 7000 or 12th/13th gen because as it is it could barely keep a stock 10900K in check with Kryonaut X and 3000RPM fans in a 16C ambient environment. This is all personal anecdotal evidence from a non-professional, so YMMV.

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Yeah but where are you supposed to go north of 250w apart from water or aio

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The Ice Giant ThermoSiphon

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You taking the piss?

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Nope no you are not

Good god

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at 150$ its not that much more than the D15 but so much more cooling, still the D15 is damn good

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380 aussie yuan, mmmm nah thats double a D15

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ah its 160 in US, 150 if you get it at micro center
for that price its a solid investment, only thing I’ve seen that makes it buckle is a 7950X and that’s because AMD wouldn’t budge on cooler compat. and made the IHS so damned thick

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Yeah if you are looking for a direct die solution you will have to go with the Thermal Grizzly delidding tool and the contact frame along with the lapping tool like Jay is going to do with his 7950x :wink:

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I guess it’s a combination of surface area, coldplate and heatpipe design.

Most big air coolers are on par, so much so that Noctua is still not releasing a new NH-D cooler. The maket is also shifting towards high end water coolers for high heat generating parts so most users can’t justify spending 90$ for an air cooler instead of 120$ for an AIO if the performance disparity is quite large.

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There’s always the option of not buying one of those power-hungry CPUs. Send a message to the manufacturers — that obscene power consumption is not wanted — in the only language they understand ($ale$).

It would also help if YouTube tech channels stopped listing stupid framerates like 621FPS (in some popular ‘esport’ title) for high-end systems/cards. If they labelled anything over 120FPS as “good enough”, gave them all the same-length bars on the charts, and then sorted the resulting top spot tie by price or power consumption instead, then normies would stop wasting money on ePeen cards that give them +10% visual fidelity for +150% power consumption and +100% price. But that’s another issue. /rant

I used the NH-D15S for the good part of a decade when nothing else could really touch it (and still fit in a ‘normal’-sized case). Now I use the NH-P1 in a completely silent and passive system. The same excellent design features and build quality are in play, except now there are thicker fins, spaced out a bit more, for improved natural airflow.

Noctua knows their stuff.

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sure but i don’t mind the power consumption as long as it translates directly to performance

according to who’s metric? yours? that’s incorrect at best and abject at worst

[citation needed]

i think the issue is inwards my dude

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I don’t know about the manufacturing process they use at Noctua nor have the D15 but generally speaking it also comes down to how well the heatpipes are attached to the base and the fins. For example cheaper heatsinks can only have the fins pressed on the heatpipes as opposed to soldered. Maybe Noctua perfected the soldering process and choice of alloys among other things. I am not saying this is the case, maybe some other manufacturer does it even better than Noctua, I really don’t know. But these details still may play a role in what separates the great heatsinks from the good.

One question for the D15 owners. Is this cooler good for ultra silent cooling? I read that since the fins are tightly packed together (with a small gaps between them) you can hear the air hitting them. And if you lower the RPM of the fans way down, the air struggles against the dense heatsink. Reportedly the D15 and some other popular Noctuas are not built for ultra silent low RPM cooling where you need larger gaps between the fins. Have you experimented with this?

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I wonder if I could get away with a NH-D14 on a Ryzen 7950X3D >.> <.<

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“Silent” means that you can’t hear it. At all. Thus the “ultra” in “ultra silent” is redundant. You probably mean “ultra quiet”. “Quiet” things can be heard in varying degrees.

I spent quarter of a century making my actively-cooled systems as quiet as possible. The summary of my experiments and experience is that it’s simply not possible to make a silent actively cooled system. Any part at all that moves makes noise. Even some parts that don’t seem to move on the macro level can vibrate (and therefore move) on the micro level and thus make noise (coil whine on GPUs being the worst offender as far as I’m concerned).

If you want a “silent” (completely inaudible) system you need to go with passive cooling for everything and be very selective with power budgets and parts. It’s not possible to build a high performance gaming rig that is silent. It is possible to build a modest gaming system that is silent. It is easy to build a basic gaming system that is silent.

All fans make noise. The fan motor makes noise, the slicing of the fan blades through air makes noise, the air rushing through a case (or through a fin stack) makes noise. Air molecules hitting fins is a real phenomena that primarily happens on the turbulent “downstream” side of a fan. Thus if you take a NH-D15 and put two fans on it, one will be in the middle (behind the front stack) and pull relatively laminar air through the front stack whilst pushing turbulent air into the rear stack. That turbulent air hitting the fins of the rear stack is where most of your noise comes from. That arrangement will be less than 2x as performant, but more than 2x as noisy, than an arrangement where you have a single fan pulling air through the rear stack and no fan in the middle.

All twin stack air coolers that support up to two fans in a similar arrangement have the same issue. It’s a physics thing, not a Noctua thing. Dual-stack designs deliberately sacrifice silence for performance.

The quietest air coolers you can have are deep, single-stack with the fan at the rear and the edges sealed to stop air from sneaking in at the edges. At low RPMs air sneaking in through the edges seriously undermines the performance of all fin stacks, as air always follows the path of least resistance. If you seal the edges you force incoming air to follow a relatively laminar and quiet path through the stack and at that point it doesn’t matter. Even a ridiculously slow fan will perform well enough. Virtually no-one places fins so close together that airflow is a problem. The problem is that virtually no-one seals the edges, so leakage undermines performance and adds to noise.

The rabbit hole goes deeper — much deeper. Pursue silence long enough and eventually you get to the point where you are minimising fan motor resonances within the fin stack by chocking the fins.

Word of advice: Don’t go that deep. In 2023, 100% “silent” is easier than 99% “ultra quiet”. Sure, you have to recalibrate your expectations, but if you are able to do that then you can save yourself 20+ years of noise-minimisation effort by skipping straight to passive cooling. In that case Noctua’s NH-P1 is your friend.

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Thank you. Yeah, “ultra” before the “silent” is indeed redundant. English being my second language might not have helped :slight_smile: . One interesting tip I’ve learned (in one of the Optimus Tech’s Alpenföhn Black Ridge videos) was how noisy the turbulence can be on a really dense finstack when the fan is mounted directly on the fins without any gap. Just leaving a small gap (and sealing the sides) eliminated this noise. But you can’t do that on every cooler.

As for the NH-P1, I have bought a used Scythe Orochi some time ago but I have to make a mounting bracket for modern sockets. These two monsters should be pretty similar. I am looking forward to experimenting with it.

Sealing the edges is a good idea. Do you mean sealing the sides of the heatsink too or just the edges around the fan?

I also have the Alpenföhn Black Ridge with its very dense finstack so I could experiment with a turbulent noise and its elimination myself. I am using this cooler right now on a 65W Ryzen with low RPM 120 mm fan and it is really impressive cooler.

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I see no reason why you wouldn’t be able to.
It’s a massive cooler, it’s a good cooler, you won’t just be able to get away with it, you will do pretty good with it.