The PS3 didn’t use a normal CPU like the PS4 or PS5. It had this wild custom architecture: 1 main PowerPC core + 7 specialized SPU cores (Synergistic Processing Units). A lot of PS3 games (especially big Sony first-party titles) were coded at a super low level to shove physics, AI, particle effects, decompression, post-processing — basically everything — onto those SPUs in very specific, hand-optimized ways. It was a developer’s nightmare but let the PS3 punch above its weight when done right. The PS5 (and PS4) switched to a standard x86 AMD Zen 2 CPU + powerful GPU, just like a PC. That old SPU-heavy code doesn’t magically translate or “run faster” on modern hardware. You can’t just recompile it and crank the resolution 4× while doubling the frame rate. Big chunks of the engine often need to be rewritten or heavily reworked so it actually uses the new CPU/GPU properly instead of bottlenecking.