shanndogg
These past three responses are exactly what I was hoping to hear as I have two Hybrids on the way. I also plan to replace the stock fans with Noctua. I understand the want for a premium products stock fans to perform better. But, I must say after finally buying some Noctua's and trying them for myself there is no comparison to any other fan I have ever used. They are that good. Regardless of that, I was also going to use my MB fan headers to control the fans so I'm not surprised some are disappointed with the noise if they leave them plugged in through the card.
I have my Hybrid cooler's fans connected directly to a couple of molex-to-5v fan-adapters, not through the card itself,
which makes them run at very low speeds (even tried replaced the stock EVGA fans with Corsair SP120 fans).
But still, the pumps on both of my Hybrid kits are extremely loud (buzzing noise is coming from the pumps them-self, not the fans).
And since it happened to both of the hybrid kits (and the buzzing they make is also identical) i doubt replacing/RMA'ing them will fix it,
+ the chance of getting 2 broken Hybrids kits in the same shipment is pretty much impossible.
To me, that indicates that's it's an ongoing problem with pretty much all the Hybrid kits.
But of course, i could have just been 200% unlucky, but i doubt it.