A RISC-V "PC" can now run a choppy rendition of The Witcher 3

In context: The RISC-V chip architecture is just ten years old, while the x86 standard was first introduced in 1978. Yet, someone is trying to bring a somewhat working emulation of Intel's CPU technology to the newer, open-standard instruction set with moderately successful results.

Developers working on the Box86 and Box64 emulation projects want to run "triple-A" PC games on the RISC-V architecture. They started with The Witcher 3: Wild Hunt, the award-winning action CD Projekt Red RPG released on PCs and consoles in 2015. It is a complex, graphically intensive game that can present a significant challenge for the RISC-based CPU ISA.

Computers with RISC-V PCs aren't too common. The Box64 developers got their hands on a Milk-V Pioneer manufactured by Sophgo, a 64-core RISC-V PC equipped with a PCIe slot. They used that slot for an AMD Radeon RX 5500 XT GPU from 2019.

The developers call Box64 a "Linux Userspace x86-64 Emulator with a twist" on GitHub. The program can run x86-64 Linux applications, including games, on non-x86 CPUs such as Arm. The emulator exploits native versions of some system libraries, such as libc, libm, SDL, and OpenGL, using dynamic recompilation (dynarec) to translate x86 code on the fly.

Emulating x86-64 instructions on the RISC-V architecture can be challenging. The Box64 developers explain that the open ISA lacks many "convenient" instructions for a proper dynarec effort, which means that more native instructions are needed to emulate the same behavior. This complication has detrimental effects on translation efficiency.

Despite the task's complexity, the coders made Box64 compatible with relatively complex titles like The Witcher 3. A brief YouTube video shows the game runs at 15 frames per second at max. Unfortunately, the audio was too choppy to be included in the final rendition of the clip.

It's likely to take a very long time before RISC-V machines become a threat to x86 supremacy for PC gaming. However, progress could improve at an accelerated pace if the chip technology gained enough traction among developers. A year ago, the RV64 DynaRec engine could only support some "easy-to-run" native Linux games. It can now run a more intense Windows title, albeit poorly, but it's at least a step in the right direction.