PS5X Emulator Finally Runs PlayStation 5 Games on Xbox Series X in Developer Mode

Xbox Series X owners can now boot certain PlayStation 5 titles on Microsoft’s console through an experimental port called PS5X. Developer Devran Cosmo Uenal built the project by adapting the open-source KytyPS5 emulator, which normally runs on Windows and Linux PCs, into a UWP application that operates exclusively inside Xbox Developer Mode. His September video showed the PS5 build of Quake II running with an Xbox controller, and three additional titles soon followed.

Those games include the GEX Trilogy, Hellboy: Web of Wyrd, Marvel Cosmic Invasion, and Quake II. Notably, three of them respond to Xbox controller button inputs, and all of them generate sounds. Quake II exemplifies the current state of performance best, often running at 25 to 45 frames per second but occasionally dropping below 20 and experiencing substantially delayed controller response. None of these four titles are tied to the PS5, and further reports show that even less demanding titles, such as Astro Bot, can only reach a whopping 10 frames per second in Xbox tests.

Both consoles have very comparable hardware: Zen 2 CPU cores, RDNA 2 graphics, and a standard 16 GB of GDDR6 RAM. This means that PS5 game code that has previously been compiled for x86-64 processors can simply be moved over to the Xbox’s native CPU without requiring a complete rewrite for the foreign hardware. The KytyPS5 on PC interprets PS5 graphics commands and must rewrite shaders for Vulkan. However, because Xbox Developer Mode only supports DirectX 11 and 12, Uenal had to go back to the code and rewrite the rendering route for Direct3D 12, as well as use Mesa’s spirv_to_dxil tool to convert shaders, with some AI tools assisting with the conversion process.

Microsoft’s Developer Mode throws a wrench in the works by limiting game memory to 5 GB and app memory to 1 GB. A standard retail Xbox game can utilize approximately 13.5 GB of the console’s entire 16 GB. Any requests that exceed the 5 GB limit are flatly denied. This leaves the PS5X project running on less than 37% of the capacity available to a regular Xbox title, therefore ruling out most current-gen releases and requiring them to get creative with memory allocation and shifting to keep under the restriction. Microsoft only lifts the restriction if you execute code through the Visual Studio debugger, which is unlikely to happen very often.

According to Uenal, the PS5X is more of a long-term hobby project, designed for experimenting with PlayStation homebrew and a few other totally acceptable items and game backups. It is missing Sony firmware and decryption keys, therefore compatibility is currently quite limited. Any improvements made to the PC version of KytyPS5 must be re-written for the DirectX renderer before they can even consider appearing on the Xbox, and given the store policies for emulators and the normal retail environment, it appears that the project is stuck with running in Developer Mode – no modifications to the standard environment exist yet, so for the time being, it is only a proof of concept.