The alpha has more surface area the SLK900A has more mass... who knows... a guy over at overclockers.com does this with a panaflo la1 80mm and got great quiet results from the 80mm...
I bought the SLK900 to use the 92 mm fan, so I could go even quieter, but I'm realizing that the 92 mm fans for the noise levels that I want aren't going to give me any more cfm than a good 80 mm fan. Plus, because the fan is bigger on the 92 mm fan, there is a larger dead spot in the most critical area of the heatsink. If I do use the SLK900, it will probably be with a 80 mm fan as well.
Why is everyone going nuts over the SLK900? Is it because of the capability to use a 92 mm fan? I'm just trying to understand why someone would pick it over the Alpha hs.
Thanks again.
Sal