Can't seem to get all my cards work. Always after a bit of mining, one card goes to 0h/s which is annoying.
so you just lower intensity for that one card.
thats what gpu_conf is for :
"gpu_conf" :
[
{ "id" : 0, "intensity" : 80, "worksize" : 8, "threads" : 1},
{ "id" : 1, "intensity" : 40, "worksize" : 8, "threads" : 2},
{ "id" : 3, "intensity" : 30, "worksize" : 8, "threads" : 2},
{ "id" : 4, "intensity" : 90, "worksize" : 8, "threads" : 1}
]