Looks like the fan in the Core V1 is 800rpm, 13dBA.
The Noctua:
800 RPM Acoustical Noise 18,1 dB(A)
550 RPM Acoustical Noise with L.N.A. 10,7 dB(A)
So if you are wanting things as silent as possible, the Noctua (with the Low Noise Adapter) is the way to go.