PS5 Runs PS3 Emulation? Digital Foundry Puts RPCS3 to the Test
Digital Foundry has tested PS3 emulation on a hacked PS5 running the RPCS3 emulator natively. The results reveal a mixed bag, heavily dependent on how a game utilizes the PS3's unique Cell processor—specifically, its SPUs (Synergistic Processing Units).
"The PS5's Zen 2 CPU is classified as C-tier by RPCS3's developers for PS3 emulation."
The Winners: Great Visuals for Lightweight Titles
Games that do not heavily rely on the Cell's SPUs run exceptionally well, often with significantly improved visuals.
- Ridge Racer 7: Runs at 4K/60 FPS.
- Resistance: Fall of Man: Achieves 4K/30 FPS.
- Heavenly Sword: Delivers a near-locked 30 FPS at a staggering 5120x2880 resolution.
- MotorStorm Trilogy: The original runs at 1440p/30 FPS, Pacific Rift hits 4K/30 FPS, and Apocalypse becomes stable after disabling MLAA.
The Losers: CPU-Intensive and SPU-Heavy Titles
The PS5's processor struggles significantly with titles that pushed the original PS3 hardware to its limits.
- CPU-Intensive Struggles:
- GTA IV: Drops to approximately 17 FPS at just 720p.
- Metal Gear Solid 4: Performs worse than on the original PS3 hardware.
- God of War: Ascension: Deemed completely unplayable.
- SPU-Heavy Challenges:
- Killzone 2: Performed below native PS3 levels due to its reliance on SPUs.
- Killzone 3: Showed improvement after disabling MLAA, managing to maintain a steady 4K/30 FPS.
The Root Cause: A CPU Bottleneck
The primary limitation is the PS5's Zen 2 CPU. RPCS3's developers classify this processor as C-tier for emulation. Newer CPU architectures, such as AMD's Zen 4 and Zen 5—which support the critical AVX-512 instruction set—perform significantly better.
The Future: Full-Speed Emulation May Require a PS6
While the performance ceiling is clear, the path forward for full-speed PS3 emulation on a console remains uncertain. Digital Foundry suggests that a future console, potentially the PS6, could have a CPU capable enough to handle the PS3's demanding architecture. Whether Sony would ever support official PS3 backwards compatibility via emulation remains an open question.