Originally Posted by doyll
That is basically what reference coolers are doing now.
True, but I haven't seen many reference coolers that can stay below 25dB at 4500rpm
They say 18dB, but I highly doubt that figure in a real life situation.
Heck, you could even just copy the reference design but use a higher quality 80mm (maybe even 92mm) fan, denser fins, and seal all the openings between the intake and the exhaust.
I like your big heatsink idea though for a single card setup, probably much easier to execute and whisper quiet.