PlayStation 5 tested as a PS3 emulation console with RPCS3
Cell processor emulation remains the main limit, but the PS5 GPU can push some PS3 games to 4K or 5K.
Digital Foundry is exploring the Linux implementation on PlayStation 5. Things that were previously impossible, like running old games through emulation on a modern console, are now relatively simple thanks to advancements in PC emulation for PS5-Linux. For this, they used RPCS3 running natively on the console. This is not an official Sony backward compatibility feature, and it requires a PS5 on exploitable firmware.
In this case, RPCS3 runs as a native Linux application, without Proton translation. Digital Foundry used the RADV driver and installed Linux on an SSD in the PS5’s M.2 slot.
Some PS3 games scale well on PS5
Early PS3 titles such as Ridge Racer 7 and Resistance: Fall of Man were able to run at their original performance targets with much higher internal resolutions. Ridge Racer 7 was shown running at 4K 60 FPS, while Resistance: Fall of Man also reached 4K output, although with frame pacing issues.
Ridge Racer 7 & esistance: Fall of Man, Source: Digital Foundry
Heavenly Sword showed one of the stronger results. The original PS3 version could drop below 30 FPS at 720p, but Digital Foundry was able to run it close to 30 FPS at 5120×2880. That is a 16x increase in pixel count over the original 720p target.
The same was not true for heavier PS3-era games. GTA IV and Metal Gear Solid 4 were limited by CPU emulation rather than GPU performance. Digital Foundry notes that raising output resolution to 4K made little difference to frame rate, which points to Cell SPU emulation as the bottleneck.
Killzone and MotorStorm show mixed results
Killzone 2 struggled on PS5 through RPCS3. Digital Foundry suggests this is linked to heavy SPU use for animation, AI and post-processing. Killzone 3 was more successful once MLAA was disabled through RPCS3 patches. With that change, the game could often reach 30 FPS at 4K, although some scenes still dropped into the 20s.
God of War Ascension, Killzone 3, Source: Digital Foundry
The MotorStorm trilogy performed better. The first MotorStorm ran at 1440p with a 30 FPS target, while MotorStorm: Pacific Rift reached 4K at 30 FPS. MotorStorm: Apocalypse also ran close to its original 30 FPS target after MLAA was disabled.
PS5 has enough GPU power to raise resolution far beyond original PS3 output in many games, but the Zen 2 CPU struggles when games rely heavily on the Cell processor’s SPUs. Digital Foundry suggests that full-speed PS3 emulation may be more realistic on next-generation console hardware, should there be a way to install Linux, of course.
Source: Digital Foundry
