Sony announced a while ago that the PS5 would be backward compatible with the PS4, and during Sony’s The Road to PS5 stream, lead system architect Mark Cerny spoke briefly about this, offering some more details- and it looks like the console won’t have complete backward compatibility with the PS4, at least at launch.
Cerny confirmed that the PS5 will be running PS4 games at “boosted frequency” on a system level, and that the boost will be “truly massive this time around.” However, he went on to explain that not all games can handle this level of boosting, which means testing has to be done on a title-by-title basis. As such, the implication here is that not all PS4 games will be playable on the PS5 at launch.
“Results are excellent,” Cerny said. “We recently took a look at the top 100 PlayStation 4 titles as ranked by play time, and we’re expecting almost all of them to be playable at launch on PlayStation 5.”
Watch the video below. It’s timestamped to the relevant part, so just hit play. No mention was made of legacy support as far as backward compatibility was concerned.