I got 2 of the "120mm Scythe S-FLEX SFF21D Fan 800 RPM" for the front and 1 "120mm Scythe S-FLEX SFF21E Silent Fan 1200 RPM" for the back of my antec 900. I thought these fans were the best money could buy for silent fan, silent my backfoot!!. I havent used the stock fans that came with my 900 so I cant compare the diff, but these fans are deff not silent. I thought it was the cpu and the top 200mm fan thats making most of the noise, but its not its my fans that cost £30 all together. I feel a tad ripped off.