hello, after the last update firmware, my rate was 60GH / s, I looked and after several attempts I handed voltage textbox and then after a reboot everything is back ok.
I have all the updates to make
Sorry for the bad English, I use a translator
What I got from bitmaintech was
"After you finish the firmware, please go to "Miner Configuration-->Advanced settings" and set the frequency to default value, click "Save&Apply", all would be better."