Well, i dont know much about the fans, but i would get the 2 8cm fans if that and the 12cm fans are the same cfm. mainly becuase i think thery would be a bit cheaper, but then again, they may be louder.
They may be louder because if they both push the same cfm, then the smaller blades would have to move faster to keep the same amount as the larger, 12cm fans.
But then again, sound factor also has to do with the type and quality of the fan u get...maybe get a couple tornado's if ur gonna sleep in there

j/k those things r loud....lol
and yes,
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