The PlayStation 5 backward compatibility with PlayStation 3 games, which is rumored to be in the works, may be held back by some important technical limitations related to the Cell processor that powered the console.
The tech experts at Digital Foundry commented on the possibility of native emulation of the PlayStation 3 on the current generation console by Sony, highlighting how the system's Cell processor's SPUs co-processors could heavily hold back backward compatibility, as the whole processor doesn't map well to modern x86 processors, and games making heavy use of SPUs could have significant performance issues, as it happens on PC via the RPCS3 emulator without patches. One way to work around this issue would be to release games that don't rely heavily on the SPU, such as simpler, smaller titles, but that would kind of defeat the purpose of backward compatibility, as most first-party titles that players would like to play on a modern system take full advantage of the Cell processor. Digital Foundry mentions Killzone 2 as a game that is likely never getting emulated due to these issues. Still, some PS3 games could run decently well on PlayStation 5 and possibly even better than on the original hardware, such as some bad ports that only used the Cell CPU's main core. Among the improvements could be better performance and improved image quality.
As it's Sony's more technically complex first-party PS3 titles that players want to play on PlayStation 5, Digital Foundry theorizes that these games could be worked on individually instead of having an emulator that would attempt to run multiple titles so that they could be made to run on very different hardware than intended, doing GPU compute instead of relying on SPUs, for example.
As of now, PS3 games are playable on PlayStation 5 only via game streaming. Hopefully, the Japanese company really did make a breakthrough to soon allow some of the excellent games released on the older system to be playable on modern hardware.
