The disk drive is quiet on mine, except when it first starts up, but the fans can get pretty loud when playing Killzone. It's the only thing I'm disappointed with.

It's awesome. Just wish the fans weren't so loud when playing Killzone. Pretty disappointed in the noise it can make.

I've still yet to see a video of a "whisper" quiet PS4 running Killzone, so unfortunately I guess it's just a loud console when the hardware is stressed.