PS3 emulation tested on PS5 through Linux, and the results are a mixed bag

After recently putting a Linux-powered PS5 setup through a path tracing test, the experts at Digital Foundry are back with another experiment, this time to show why Sony has never officially delivered PlayStation 3 emulation on the PS5. Using RPCS3, the most advanced PS3 emulator available, running natively on a hacked PS5 with firmware 6.02 or earlier, Digital Foundry tested a variety of games, with some running great while others struggled to achieve even PS3-level framerates.

Games that don't heavily rely on the PS3's exotic Cell processor and its Synergistic Processing Units (SPU) ran surprisingly well. Ridge Racer 7 ran at a locked 4K 60 FPS, while Resistance: Fall of Man hit 4K 30 FPS with only minor frame pacing issues. Heavenly Sword was arguably the most impressive result, scaling from its original sub-30 FPS 720p performance to a near-locked 30 FPS at a staggering 5120x2880, a 16x increase in pixel count over the original output.

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The MotorStorm trilogy also held up well. The original MotorStorm ran at 1440p 30 FPS, Pacific Rift reached 4K 30 FPS, and Apocalypse also hit its performance target after MLAA was disabled through RPCS3 patches. In short, for games that didn't push the Cell processor's complex SPU architecture, the PS5 delivers a genuinely impressive upgrade in visual fidelity.

On the other hand, heavier PS3-era games that pushed the Cell architecture to its limits performed poorly. GTA IV, for instance, ran in slow motion, dropping to around 17 FPS at 720p regardless of resolution settings, confirming this is a CPU bottleneck rather than a GPU one. Metal Gear Solid 4 suffered similar issues, often performing worse than the original PS3 hardware. God of War: Ascension, one of the PS3's most demanding titles, proved too much for the emulator even with SPU-intensive MLAA removed.

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Killzone 2 also struggled, with SPU-heavy animation, AI, and post-processing dragging performance below PS3 levels. Killzone 3, however, was more forgiving once MLAA was disabled, maintaining a relatively stable 4K 30 FPS across much of the game, making it better suited for emulation than its predecessor despite launching two years later.

While the results are interesting, Digital Foundry concludes that the PS5's cut-down Zen 2 CPU is simply not well equipped for Cell SPU emulation. The PlayStation 3's processor is fundamentally different from the x86 CPUs used in modern consoles. When the RPCS3 team released its CPU Tier List, AMD's Zen 2 CPUs were classed as "C-Tier." On PC, the RPCS3 emulator recently gave a 7% FPS boost to demanding titles across all CPUs by optimizing SPU usage patterns.

With support for new instructions, AVX-512 specifically, AMD's newer Zen 4 and Zen 5 CPUs sit at the top of RPCS3's performance tier list. Digital Foundry suggests that full-speed PS3 emulation may only become truly viable on PlayStation 6, where the Zen 6 CPU architecture should have the horsepower and instruction set support to handle the Cell without compromise. That said, while PS3 emulation on PS6 could be a killer feature for the console, it remains to be seen whether Sony ever moves the idea beyond the drawing board.