The pixel wizards at Digital Foundry have run extensive tests on Ratchet & Clank: Rift Apart for the PC, and in doing so found that the game would definitely not have been able to run on the PS4.
DF attempted to run the game on a PS4 hard drive — a SATA II 5,400 RPM drive — and found that it doesn’t run properly and crashes. A system close to minimum specs was used for the tests, equipped with a PS4 drive ripped from an old console and installed on a PC.
However, the game stutters and freezes once it shoots Ratchet through the various worlds during the portal sequence. It’s this section in particular that Insomniac Games used to demonstrate the seamless transitions between worlds with minimal load times — something made only possible on PS5 and NVMe SSD.
All of this testing essentially confirms that the game would not have been possible on PS4, particularly as that consoles hard drive was considered dated even during its lifecycle.
Ratchet & Clank: Rift Apart is now available for the PC and was released for the PS5 in June 2021.
[Source – Digital Foundry]