It's not my best work, but apparently better than the fan selection from technobit...

http://www.bilder-upload.eu/thumb/429874-1392409724.jpg

http://www.bilder-upload.eu/thumb/5a2612-1392409811.jpg

http://www.bilder-upload.eu/thumb/d9e285-1392409832.jpg

http://www.bilder-upload.eu/thumb/2e785f-1392409847.jpg

my cgminer parameters: --hexminer8-set-diff-to-one 1 --hexminer8-chip-mask 255 --hexminer8-voltage 920 --hexminer8-options 8:220

yes i "under"-clocked it, but it runs rock solid with this values

about 60db directly by the bottom fan