Until now, expanding the storage space on your PS4 from the standard 500GB to 1TB built into the system involved opening up the system and sliding in a new internal drive. That process won't be necessary for much longer, as the PS4's upcoming Version 4.5 firmware will add support for USB 3.0 hard drives up to 8TB.
Just before the PS4 launched in 2013, Sony noted that PS4 games had to be "cached to the hard drive to ensure a smooth gaming experience." If streaming all that game data to the system over a USB connection was a bottleneck at launch, it's apparently no longer a concern for Sony (at least for drives that support USB 3.0's faster data transfer rates). Games, saved data, and captures screenshots and videos will all be storable on external drives, and that data will show up on the main system menu without the need to shuffle them to the internal storage.
The announcement of the external HD support comes as the beta of firmware version 4.5 rolls out to selected PS4 users today. That firmware also brings the ability to use in-game screenshots as home screen wallpapers, streamlined interface improvements, and new support for stereoscopic 3D Blu-Ray discs.
Source:
https://arstechnica.com/gaming/2017/02/ps4-will-soon-support-external-usb-hard-drives/ [arstechnica.com]