Don't get me wrong. The cooler works in a 2U form factor server. The problem with the cooler is the fan. The fan whistles at around 5000 rpm. BUT, if you put your hand on the other side of the radiator, you won't feel much air. I don't know where they get 28cfm from, but it's not at 5000rpm. I ordered another fan, Noctua, for this radiator. For the total price I could have gotten a much better cooler. So keep that in mind when purchasing.