C.C.O., stands for Combo Cooler Option, is another exclusive hardware design on ASRock advanced motherboards. C.C.O. provides the flexible options to adopt different CPU cooler types and matches your socket LGA 775 or LGA 1156 / LGA 1366 CPU cooler in the respective holes. Once again, ASRock has successfully expanded the utilization of PCB by the exclusive C.C.O. design.