A 120mm fan (4") is quite a big fan and to have 8 computer fans that run on 12V instead of a few icecaps is quite alot of fans and would need a significant canopy to just hold them all. The icecap moves a very large amount of air and is fairly quite. I have one icecap fan blowing in my 250W MH
hood on my 20 gal
tank. I have the thermal sensor close to the lamp and reflector and the fan very rarly kicks into high gear.
I have see computer fans that are running and if you put your hand on the inlet or outlet of the fan you hardly know its moving air. The icecap moves a very large amount of air in compairson IMO