reset all overclocking settings if you used any , watttool , wattman , afterburner ...ect
turn off your pc
switch the bios switch for each cards to the opposite way
reboot your pc
dont overclock or undervolt ,
start the miner program let see what happening

always the same gpu hang on open cl ?
if yes  , find out which one is that gpu , easy way to do that turn off the mining for that card from claymores mining software , if its gpu 1 , then push number 1 on the keyboard , you going to see a msg in the dos window , gpu 1 mining is disabled . Few minutes later that card going to cool down , fan willl be turned off , so you can see the card with gpu1 , fun not spinning .
turn off you pc , remove the problematic card , restart the pc and let the mining program run for a few hours .

hang on open cl usually happening when the bios is modded incorrectly , or the card is way overclocked or undervolted ...