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It certainly won't be until ps6, that's for sure if it even happens. Backwards compatibility won't be too big of a deal because they are going from x86 to x86 and they have access to Apis and such. This won't be like going from cell to x86 or powerpc to x86.
MCM design won't come into affect for ps6 generation imo. MCM has it's own set of quirks that only makes sense if you are scaling up very high end GPUs. While the GPU inside of the ps6 will be leagues better by todays standards, I don't think it's likely that it will be using MCM design similar to how the CPU inside of the PS5 is monolith despite the desktop Zen CPUs being all chiplets. But we will see since it's too soon to tell.
PC Specs: CPU: 7800X3D || GPU: Strix 4090 || RAM: 32GB DDR5 6000 || Main SSD: WD 2TB SN850
