I found a good param for cgminer for keeping your gpu cool :
-auto-fan --temp-target 70
I also added --auto-gpu just in case if I see air temp over 30... And I'm not sure why but if you setup GPU and RAM speeds from cgminer it runs cooler...
EDIT: 7870 cmd line setings... --temp-target 68 --auto-fan --gpu-fan 50-100 --auto-gpu --gpu-engine 1100-1250 --gpu-memclock 625