They don't have to do anything with regard to S|X or PS5. They aren't going to write whole new software for the other two platforms when they work well enough...
Oh wait. Xbox runs on Windows, so the Xbox version is already essentially the PC version. The S|X is basically an amped up One, so it's like upgrading a PC. Runs the game better (and it does).
PS5 runs PS4 games on an emulator. They'd need whole new code to make it for the PS5. Good luck with that. They sell most on PC, so they aren't going to make new code for a minority of their base.
Sony fans seemed to make fun of Xbox for basically just upgrading the One, but this is one of the benefits. Developers don't need whole new code for the PC, or even the X|S. Eventually the One won't be able to handle the new games, and that's where the X|S comes in. It's just like upgrading a PC... old PCs can't play newer games.
You can thank Sony for making it harder for developers to incrementally upgrade. An emulator won't look as good, so... oh well? Why is that FDev's fault?
The PS4 was an AMD Jaguar CPU with a custom AMD GPU very similar to Xbox One architecture. The Xbox Series and PS5 are basically AMD Zen 2 CPUs with RDNA custom GPUs . Again very similar in architecture.
PS5 backwards compatibility is not an 'emulator' just as Xbox Series isn't either.
The Xbox I won't deny has much more refined backwards compatibility than PS5 in terms of implementation from the system.
As for 'wasting' time improving the game on both XS and PS5 I just don't agree. Both would benefit from enhanced versions rather than relying on backwards compatibility.
Commercially as well as technically. That's for FDev to decide and we all know the current state. 'no plans'.
Edit, backwards compatibility background:
From Eurogamer
'PlayStation 4 Pro was built to deliver higher performance than its base counterpart in order to open the door to 4K display support, but compatibility was key. A 'butterfly' GPU configuration was deployed which essentially doubled up on the graphics core, but clock speeds aside, the CPU had to remain the same - the Zen core was not an option. For PS5, extra logic is added to the RDNA 2 GPU to ensure compatibility with PS4 and PS4 Pro, but how about the CPU side of the equation?
"All of the game logic created for Jaguar CPUs works properly on Zen 2 CPUs, but the timing of execution of instructions can be substantially different," Mark Cerny tells us. "We worked to AMD to customise our particular Zen 2 cores; they have modes in which they can more closely approximate Jaguar timing. We're keeping that in our back pocket, so to speak, as we proceed with the backwards compatibility work."'
Source:
On March 18th, Sony finally broke cover with in-depth information on the technical make-up of PlayStation 5. Expanding …
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