Ray tracing has traditionally been associated with GPUs specifically designed for hardware-accelerated ray tracing. However, older AMD GPUs, including the GCN-based models like the Radeon HD 7970, have demonstrated the ability to run ray tracing through software emulation. A notable example of this was highlighted by Clewless Clay on YouTube, showcasing an AMD Vega 64 running the game *Indiana Jones and the Great Circle* at above 30 FPS.
Software-Based Ray Tracing Performance
The performance of software-based ray tracing has proven to be quite impressive. A YouTube channel called “no RTX no problem” showcased the RX Vega 64 playing *Indiana Jones and the Great Circle* in Linux Fedora 41 at 1080p resolution with 50% scaling (effectively 720p) and medium graphics settings. The frame rates ranged between 50 to 60 FPS on average.
Comparative Performance with Newer GPUs
Another YouTuber, BK Benchmark, demonstrated the RX 5700 XT running the same game at native 1080p with the same settings. The newer graphics card achieved significantly higher performance, maintaining an average frame rate between 70 to 80 FPS.
Technical Implementation of Ray Tracing on AMD GPUs
Ray tracing emulation on AMD GPUs relies on Linux’s RADV driver, an open-source alternative to the official AMDVLK Linux driver, which enhances AMD GPU capabilities. Joshua Ashton, who developed this emulation, achieved it by simulating AMD BVH intersection instructions in software. His initial experiments with RT emulation began in 2021, expanding to support architectures from GCN 1.0 in 2022, and achieving full stability by 2023 with a reported “100% pass rate” according to Phoronix. This technology can even be activated for benchmarking on RDNA2 and RDNA3 architectures using a specific debug option.
Future Implications for Gaming
While Linux-based ray tracing emulation does not stand up to the performance of newer GPUs equipped with hardware acceleration, it provides essential functionality for enabling modern games on older graphics cards. For instance, *Indiana Jones and the Great Circle* is one of the early titles mandating ray-tracing-capable graphics hardware, indicating a potential trend in future titles requiring similar capabilities. Emulating ray tracing might be the only means for users with non-RT GPUs to enjoy these upcoming games, assuming the ray-traced graphics can be adjusted to maintain playable performance.
Limitations of Ray Tracing Emulation
Currently, the major limitation of this ray tracing emulation is its exclusivity to Linux operating systems, as it is based on an open-source driver tailored for Linux. There are no current plans to extend this feature to Windows operating systems, including Windows 10 or Windows 11, nor is there any development aimed at adapting it for Nvidia GTX graphics cards. This restricts the functionality to users running Linux on older, pre-RDNA2 AMD graphics cards.