I just got a replacement 15" Haswell rMBP that is perfect in every respect... except that it sounds like it has an HDD in it (read-write clicks/buzzing). Obviously it doesn't have one but that's what it sounds like. Is this normal? There isn't much documentation on this (if it even is an problem) and I'm not sure if I'm just being paranoid but I thought I'd see what everyone thinks. It happens whenever I load anything (apps, navigate in safari, scroll down a webpage, etc). I've tried isolating the problem but I can't figure out what is causing this (it's not the fans, not the backlit keyboard, not either of the GPUs). All that I can think of is the SSD, CPU, or RAM. But aren't all these supposed to be silent? Of course, if this is normal then I'm probably just sounding like an idiot, but I swear my other machines with SSDs are completely silent until the fans kick in. Help appreciated!