So you had the outter fan blowing air out air from the chassi and the other one blowing air in the chassi? Or both blowing air out? I've heard both ways are bad and both ways are good.
I'm really not sure at the moment.
Push-Pull simply means installing two cooling fansâ€”one on each side of the Hydro Series H50â€™s radiator unit â€“ as opposed to simply using one fan. The first fan therefore â€˜pushesâ€™ air through the radiatorâ€™s cooling fins, while the other â€˜pullsâ€™ air through from the other side, hence the name. The combined effect of both 120mm fans results in increased airflow over the radiatorâ€™s cooling fins, which in turn results in more efficient dissipation of heat and hence lower CPU temperatures. To ensure that the fans do not compete with each other, itâ€™s important to use two identical fans, or two fans with similar airflow characteristics.