Well some people have been testing SSDs:-
We tracked down an
ADATA XPG Gammix S50 Lite, one of the slowest compatible PCIe Gen4 drives we could find at 3,900MB/s reads and 3,200MB/s writes, and stuck it into a PS5, along with another drive.
We compared the S50 Lite against both the PS5’s internal SSD and a 5,000MB/s Sabrent Rocket 500GB in a battery of tests, including load times for games like early PS5 showcases
Ratchet and Clank: Rift Apart and
Spider-Man: Miles Morales.
The verdict?
Surprisingly, even the slowest compatible SSD we could find had near-identical load times to the one Sony includes in the box.
Sometimes it’s a second slower, sometimes a second or two faster, but basically it’s a total wash.
Hopping through dimensions in
Ratchet and Clank: Rift Apart, I saw no appreciable difference with the slowest SSD in gameplay, either.
Stepping through pocket dimensions was instantaneous, and when there was a slight pause during a boss fight, I saw the same pause on the internal SSD as well.