My solution was to take some spare Noctua low-noise adapters (basically inline resistors with fan connectors attached) and just drop the max fan speed. The fan

My solution was to take some spare Noctua low-noise adapters (basically inline resistors with fan connectors attached) and just drop the max fan speed. The fan controller can freak out all it wants, it can never go above about half rpms, and it still generates a noticeable breeze through the hotswap bays. My CPU is a 7100 (ECC supported!) with a Noctua L9i so I never have problems there either. Power draw is a little high at about 70W with 8 3.5" drives spinning, but most of that is the HDDs (rule of thumb is 5W per drive) and the alternative would be spinning them down, which isn't ideal.