It just never made sense to me, to have that type of fan blow onto a that heat sink design. I reversed it as soon as I found some longer screws. Blowing air over a surface of that makes a sudden 90 degree turn causes a lot of turbulence, a better laminar flow can be achieved if the air is pulled over a surface. Plus that type of fan doesn't provide the static pressure required to make that turn. Not a fluid dynamics engineer, but I have worked with a few and seen a one or two flow test performed. Then again I never performed an actual temp survey so I could be completely wrong, fluid dynamics can be a tricky thing. Someday I'll put a temp probe on it and compare it with a lower flow Noctua and see if there is a notable temp increase. My guess is at temps =/< 210c it will be negligible. Oh, and there's the added benefit of not getting air blowing in my face.