At some point the air must get passed over or through the fans of that heatsink, otherwise it's pointless......if air gets passed through it, then there will be dust and fluff accumulation - it's inevitable unless there are filters (as anyone that tried to prevent dust in a PC case will tell you).The fan sulks air in through the vents on either side of the console then blow it out the rear of the console. It was explained in the video. Also there are a couple of small pockets that trap dust so you can easily vacuum out the dust. Again in the teardown.