Why is the G2 noisier than the G1?
[Update 14/7/2024] Shortly after I delivered this review, I had the time to conduct even more noise tests, and I discovered something annoying. Read the full story here: Noctua NH-D15 G2 Rattlegate?According to the results found on the previous page, noise output is notably higher than that of the previous cooler, at full speed and 70% of it. This is weird because the G1 and G2 fans produce about the same noise in a clear field. I spent several hours re-testing until I found out what was going on. But let’s take it from the start.
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As you can see, both fans have slight differences in noise output at full speed. The problem is that once two of these fans are mounted on the heatsinks, the noise difference between the G1 and G2 coolers is significant, reaching 4.3 dBA at full fan speed. I expected a higher noise output in the G2 cooler because of the more dense fins and the increased number of heatpipes, but not such a significant difference.
After discussing this matter with Noctua, I proceeded with more noise measurements. For starters, I tested another G2 cooler with the stock fans, which delivered similar results to the first, proving that there was no problem in the first sample I evaluated.
The next step was to install the new fans on the G1 heatsink to see if there would be any differences in noise output. To my surprise, noise output increased notably, reaching 36.6 dBA! So, the different designs of the heatsink are NOT the problem here.
Since the G2 fans had slightly increased speed compared to the G1 fans, I conducted an additional test, dropping their speeds to the ones that the G1 fans have at full speed. I also canceled their speed offset, having them run at similar speeds. As you can see, noise output dropped notably, but it is still significantly higher than the reading for the stock fans.
The last test I conducted was to use the G1 fans (NF-A15 HS-PWM) on the G2 cooler. This was the most crucial test since it proved that the new fans, once in pairs, produce higher noise output than the old ones! This troubles me a lot, given that the speed offset between the G2 fans, according to Noctua and the beat frequency theory, should not increase noise output but, on the contrary, keep it lower. But the real-life measurements show precisely the opposite!
Noise Recordings
These recordings were taken using the same equipment, with the MIC in the same place and both coolers at the same distance. Automatic gain control is not enabled since the cooler’s noise is high enough not to require it.
NH-D15 G1 Noise – 2x NF-A15 HS-PWM Fans Full Speed
NH-D15 G2 Noise – 2x NF-A14x25r G2 Fans Full Speed
Frequency Plots
The following frequency plots show the G1 and G2 coolers with their fans at full speed. As you can see, the G1’s full-speed noise is notably lower than the one the G2 registers.
NH-D15 G1 Frequency Plot – 2x NF-A15 HS-PWM Fans Full Speed
NH-D15 G2 Frequency Plot – 2x NF-A14x25r G2 Fans Full Speed
Oh how I wish you included any of the Phantom Spirit coolers, or ID-Cooling Frozn A720 in your charts. Those truly give Noctua run for their money.
Anyway, have you ever considered testing your coolers by combining them with aftermarket fans? Like, I would really like to know how would G2 perform with a pair of Shark Force 140s, or a pair of SF Megacool 140s. Off the record I mean, I don’t expect you to include that kind of tests in your regular reviews. No doubt that would make testing process an absolute nightmare to complete.
I am waiting for TR to send me some of their coolers. Hopefully soon.
I have seen 3 reviews so far, and the fins rattle at full speed. What a joke from Noctua, 150€ for what?? The fan design is a copy/paste from a car fan radiator(peugeot 308), I just don’t see the value here(plastic washers, metal bits, an extra heatpipe, etc), maybe that screwdriver is the most expensive thing, it’s a trend these days for overpriced screwdrivers.
Excellent review very easy to follow and understand it, well done.
I’m leaning towards the G1 at apx 120 eur rather G2 at 180 eur.
I would really like to buy from a European brand, and i like the esthetic.
However, these are not made far away from TR factory…. Would expect made in Europe for this price.
Still, TR phantom spirit is 60 eur.
Oh! I’m very interested to learn where the Noctua and Thermalright coolers are made. Can you share your source?
I don’t have a clue 🙂
Noctua’s heatsinks are made by Kolink
https://noctua.at/en/rascom-kolink