The silent pipe design or something similar i believe your referring to has little to do with the cpu normally and most commonly these boards still require a cpu heatsink as otherwise the cpu would just overheat straight away. So in short you need to install a heatsink and cpu fan but not necessarily the little fan - what does it say in your manual about the extra fan??
The silent pipe design tends to be put on boards to remove the heat from the north and south bridge chipsets as on my DS4 which has the pipe passing through each heatsink on the north and south bridge. This is what it is primarily for i think.
ASUS p5B fanless cooling question 
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