Hi everyone — I work at ATTO in support; and I am happy to report that with the latest driver & firmware version for the R680 (and the also the R380), the fan noise on any model Mac Pro should not be a problem.
If users are currently experiencing problems with fan noise, it is suggested that they upgrade to the latest driver & firmware version, and then completely power off the machine (has to be cold shutdown, not a warm reboot) and then power it back on. This will resolve any fan noise issues.
If anyone has any questions, please let me know.
-Nick