Game developers really want SSD, but there are problems.
- Very high speed to load game.
- Main reason: more freedom for game developer
Some HDD solution to reduce load time / streaming gameplay:
- put near object inside the game in sequential chunk of data
- replicate common objects in many places of the HDD(i.e. mailbox inside the spider-mam game)
With SSD, the loading of the game can happen simultaneously when the player look around.
Previous HDD needs to reconstruct a brand new file when a new path was downloaded, no longer the case for SSD.
Also, with the high speed to load data from SSD, the RAM would only need to contain ~ next 1 second of gameplay so data can be load on the fly, which in other way reduce the need to put more RAM.
There are different bottle neck that can happen after load the data from the SSD, and so PS5 designed a custom flash controller with 12 channels and a main custom chip and custom unit in different part of IO, decompressors, etc.
All theses lead to ~= 100x faster for PS5 compared with PS4.
PS5 also achieves backward compatibility by design and incorporate custom chip in a way to support PS4 mode, instead of putting previous chipset into new one(expensive).
PS5 was designed with a goal of only require < 1 month of learning for existing developers.
