Lets hope some sites reviews the NH-D15 vs Silverarrow IBE.
Originally Posted by Capt
You do realize that the NH-D14 came with the old fans that used the first SSO-bearing and were not PWM? The NH-D15 comes with two NH-A15 fans that are second generation SSO2-bearing and are PWM. While these fans are larger than the fans on the NH-D14, they will be much quieter because of the SSO2 bearing. I highly doubt Noctua would release the NH-D15 and make it louder than the NH-D14. The NH-D15 should theoretically be much quieter than the NH-D14 but we'll see I guess.
Noise is something very relative to each, even if its measurable, the sonic signature of each fan is different, and thus not always bigger and newers is better. SPCR has reviewed many of the newer noctuas and they still prefer the old signature sound of the Noctua NF-P14 FLX, i leave the review in case you are interested, First 140 mm Fan Roundup: Noctua, Phanteks, Xigmatek
The A15 has a smoother acoustic profile than the A14 but both sound fairly good to the ears. However, they share the misfortune of living in the shadow of the P14. The A15 and A14 have a rougher, muddier sound and neither is worthy of being a true successor.
PWM fans are not better or worst than 3pin voltage controlled fans, its just another way to control fans, and even then they have to be developed and perfected, today most of the quiet fans are not PWM, but i do expect in the years to come that we will see better PWM fans, and probably reaching the best in charts, just we are not there yet.
But not all is bad though, Noctua has the best PWM range of control in the market for someone looking for a wide range of operation, not that many PWM fans can drop below 300rpms, where most of the new noctuas can, specially for someone looking to build a very quiet setup by driven their fans to inaudible levels, the biggest problem is needing higher rpms, where noctuas sonic siganture is not the best, but then again everything is relative to each user.