Sheesh, fans set for 100% all the time in the 821 firmware... Anyone played with setting it back to something reasonable like 50% or 20, like I ran the 741's and let the temp circuit moderate the fan speed as needed to keep 90 degrees on the outlet? I guess I'll see what outlet temps I've got first, but my basement this time of year is pretty dang cold, and I'd just as soon trade off some noise if appropriate.
What's your 'minimum fan speed' setting in the Cgminer configuration?
I'm guessing it is 100.
Set it to 20 and see how the miner acts in your environment.
Note that 20 is only the minimum value and miner will control the fan speed up or down in relation with the miner temperature.