I guess that would depend on what fan. I would bet they are pretty equal. The big diff to me is the ax-7 mounts on the socket where the 8045 needs to be bolted to the mobo, more work there. The 8045 is supposed to have the fan sucking, the ax-7 blowing. For a low speed say 40cfm fan I think the 8045 would have the edge, with a high speed delta I would give the edge to the ax-7. I guess it all depends how much noise you can tolerate.