I am trying to add another GPU to my rig (580) but it will not mine, it is recognized but it will not start mining. Any recomendations?
core clock too high.
input these settings 
1168 core clock
860 core voltage
800 memory controller voltage
2100 memory clock
amdmemtweak --REF 30
aggressive undervolting on
I tried those settings however my cards fans will not even spin and it does not show the voltage/ hashrate.
is it new? maybe there is a problem with the card. have you tried it in windows?