While tinkering with the PlayStation 4, German website Computer Bild discovered that the hard drive inside the PS4 is 12.5 millimeters, an increase from the PS3′s 9.5 millimeter hard drive. In other words, thanks to the increase in size, users can replace the PS4 hard drive with a 1.5TB SATA hard drive.
While both the PS3 and PS4 support 2.5-inch SATA drives, the difference is in the actual height: 9.5mm vs. 12.5mm. This gives the PS4 a bit of future-proofing, since hard drive manufacturers will eventually manage to squeeze more space into the 12.5mm form factor.
Just like with the PS3′s drive dock, the PS4′s drive dock is fitted with Phillips-head screws, which means you can use any regular screwdriver to change the hard drive to your liking, you tinkerers, you.