its got 3 fans installed and missing the other 5, if we go by the renders on their site which had 6 fans on the radiators (one each side per rad) and 2 fans on the rear.. so yeah, maybe they didn't need so many fans after all (and can save cost leaving some of them off.. e.g. the other 3 radiator fans)

on the other hand, right now.. theres no heat being generated.. so maybe the airflow needs to be much faster to take the heat off the rads.  presumably they've done thermal simulations of the airflow and hot chips including the warmed up air blown onto them from the rads etc.. and have decided its well within spec