Much louder. I have two KS-282 cases and also a 1030SX, they've all got 300W power supplies, two of which I've now opened and put Panaflos in. They really are nearly silent. noticeably less airflow, but it's still just a little warm when i stick my paw back there. I'd totally recommend it, given that they've become more readily available and pretty cheap, too. the ones I recieved came with two-pin adapters which didn't fit the sockets in the powersupply, but those sockets slide right off the electrical prongs, and the fans plug can attach directly to those prongs.