I was playing around with the Zalman 8000 on the F-I90HD for a few days. When I had everything opened and the PSU outside of the case, the temps were pretty impressive, but as soon as I placed the PSU over the cooler, the temps raised about 6 degrees C. I think it is contending with the PSU for air or the gap is too small for air to flow through.
I've switched to the NT06 (Enermax Liberty PSU). I was expecting a bigger drop, but it performed about the same as the 8000 with everything in the case. There's 2 less fans (including crossflow), so it's extrememly quiet. Now all I hear is my Raptor.
What cpu did you have, was it overclocked with the nt06? I will be building a sg01 with the nt06 at the beginning of the summer. All the reviews of the nt06 that i can find with google arent not very comprehensive. I can find much info about people using it passively with the psu and o/c also. I will probably using the same mobo that you are using assuming some of the artifacting problems people are having are memory related and not the mobo. I'm hoping that the nt06 would allow me to oc a 4300 to the fsb limit of the mobo.