The Noctua NH-D15 G2 LBC Cooler Review: Notoriously Big, Incredibly Good
by E. Fylladitakis on August 12, 2024 12:00 PM EST- Posted in
- Cases/Cooling/PSUs
- Noctua
- Cooler
- Air Cooling
Testing Methodology
Although the testing of a cooler appears to be a simple task, that could not be much further from the truth. Proper thermal testing cannot be performed with a cooler mounted on a single chip, for multiple reasons. Some of these reasons include the instability of the thermal load and the inability to fully control and or monitor it, as well as the inaccuracy of the chip-integrated sensors. It is also impossible to compare results taken on different chips, let alone entirely different systems, which is a great problem when testing computer coolers, as the hardware changes every several months. Finally, testing a cooler on a typical system prevents the tester from assessing the most vital characteristic of a cooler, its absolute thermal resistance.
The absolute thermal resistance defines the absolute performance of a heatsink by indicating the temperature rise per unit of power, in our case in degrees Celsius per Watt (°C/W). In layman's terms, if the thermal resistance of a heatsink is known, the user can assess the highest possible temperature rise of a chip over ambient by simply multiplying the maximum thermal design power (TDP) rating of the chip with it. Extracting the absolute thermal resistance of a cooler however is no simple task, as the load has to be perfectly even, steady and variable, as the thermal resistance also varies depending on the magnitude of the thermal load. Therefore, even if it would be possible to assess the thermal resistance of a cooler while it is mounted on a working chip, it would not suffice, as a large change of the thermal load can yield much different results.
Appropriate thermal testing requires the creation of a proper testing station and the use of laboratory-grade equipment. Therefore, we created a thermal testing platform with a fully controllable thermal energy source that may be used to test any kind of cooler, regardless of its design and or compatibility. The thermal cartridge inside the core of our testing station can have its power adjusted between 60 W and 340 W, in 2 W increments (and it never throttles). Furthermore, monitoring and logging of the testing process via software minimizes the possibility of human errors during testing. A multifunction data acquisition module (DAQ) is responsible for the automatic or the manual control of the testing equipment, the acquisition of the ambient and the in-core temperatures via PT100 sensors, the logging of the test results and the mathematical extraction of performance figures.
Finally, as noise measurements are a bit tricky, their measurement is being performed manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is being recorded via a laser tachometer. The fans (and pumps, when applicable) are being powered via an adjustable, fanless desktop DC power supply and noise measurements are being taken 1 meter away from the cooler, in a straight line ahead from its fan engine. At this point we should also note that the Decibel scale is logarithmic, which means that roughly every 3 dB(A) the sound pressure doubles. Therefore, the difference of sound pressure between 30 dB(A) and 60 dB(A) is not "twice as much" but nearly a thousand times greater. The table below should help you cross-reference our test results with real-life situations.
The noise floor of our recording equipment is 30.2-30.4 dB(A), which represents a medium-sized room without any active noise sources. All of our acoustic testing takes place during night hours, minimizing the possibility of external disruptions.
| <35dB(A) | Virtually inaudible |
| 35-38dB(A) | Very quiet (whisper-slight humming) |
| 38-40dB(A) | Quiet (relatively comfortable - humming) |
| 40-44dB(A) | Normal (humming noise, above comfortable for a large % of users) |
| 44-47dB(A)* | Loud* (strong aerodynamic noise) |
| 47-50dB(A) | Very loud (strong whining noise) |
| 50-54dB(A) | Extremely loud (painfully distracting for the vast majority of users) |
| >54dB(A) | Intolerable for home/office use, special applications only. |
*noise levels above this are not suggested for daily use
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Hresna - Sunday, August 18, 2024 - link
Water-cooling is an option for people that want to operate recent-gen intel at full-power stock defaults, but it’s not the only option. The chips remain very performant if you tune them down a bit, and the efficiency increases substantially. They will never be as efficient as their Ryzen contemporaries in PPW, but their feature set might still make them worthwhile for a lot of use cases.Granted, turning down a CPU for efficiency is a decidedly unpopular thing to do, even among enthusiasts. But I think we might see it become a bit more common for them to release with more conservative performance profiles. AMD even seems to have left a good amount of headroom on their 9000 series, perhaps looking to avoid some of intels’ recent pitfalls.
Some data on 13th gen power scaling:
https://www.reddit.com/r/hardware/comments/10bna5r...
Silver5urfer - Tuesday, August 13, 2024 - link
Wasn't there a factory defect on these ? Noctua did not announce any recall but it was under investigation.https://www.tomshardware.com/pc-components/cooling...
That said the Cooler this round is overpriced. I have the Chromax Black DH15 on an LGA1200 socket. There's very minimal advantage going the G2 route. Also no Chromax edition, no G2 Chromax fans either, the heatsink cover is also not there yet. Skip it.
As for convex/concave designs, Intel LGA1700 is a disaster that must be avoided at all costs due to CPU bending, Socket PCB bending, latest RPL silicon degradation due to poor silicon engineering. There's no reason why anyone should even consider buying this cooler for that platform, not only it will be inadequate for a 13th 14th gen i9 processors but also worthless. The heat density is also higher on 13th and 14th like of 11th gen, too hot for an Aircooler.
Khanan - Tuesday, August 13, 2024 - link
It was a small problem with the first batch and was fixed quickly by Noctua / not even all were affected (afaik).rpg1966 - Tuesday, August 13, 2024 - link
The final chart that Anandtech includes is great. But I don't understand why none of the tech sites I read don't plot noise vs temp-over-ambient, maybe additionally colouring or sizing each plotted point to indicate the price.Ryan Smith - Tuesday, August 13, 2024 - link
The issue comes down to temp-over-ambient at what power level. It's a 3 dimensional function, which makes for a very ugly plot.That's why E opted for noise vs thermal resistance. TR is (mostly) constant, so it allows you to plot noise versus just a single variable on a 2D graph.
rpg1966 - Wednesday, August 14, 2024 - link
Understood. It might take a couple of charts, e.g. one at 100W, one at 200W (or whatever)? Anyway, good job with the last chart, great info.casteve - Tuesday, August 13, 2024 - link
Thanks for the review. I love the thermal resistance vs sound pressure graph...but..this is clearly an air cooler designed for much higher loads than 100W. At 100W, I'd throw the U12A and U12S on there as the competition - The U12S is half the price, and at 100W cools just fine and is significantly quieter. I'm guessing the 550rpm @ low speed is at or below your noise floor.Add the 200W results, please.
NorthRocks - Monday, August 19, 2024 - link
Currently using 2-3 original D15 models.The fact that the older models actually performs better at lower RPM makes upgrading seem bit pointless to me. The CPUs I use (Ryzen 9 7900X etc.) seldom run at maximum power.dqniel - Monday, August 19, 2024 - link
Absolutely insane price. The performance and support is good, but so is the performance and support of other companies... without the insane price.Oxford Guy - Thursday, August 22, 2024 - link
Considering how long these last and inflation, $150 is hardly insane.