The Role of GPUs in Ray Tracing: A Comprehensive Guide

Ray tracing, a computational rendering technique that simulates light behavior, has gained significant attention in the gaming and 3D rendering industries. This article explores how ray tracing works, the differences between Nvidia and AMD's GPU architectures, and what implications this has for game performance.

What is Ray Tracing?

Ray tracing is a method used in computer graphics to generate realistic images and animations by simulating the behavior of light and how it interacts with surfaces. Traditionally, this process has been resource-intensive, leading to lower frame rates in real-time applications. However, advancements in GPU technology have made it possible to perform ray tracing with reasonable performance.

While any graphics card can technically run ray tracing software, the performance and feature set differ between different GPU architectures. This article will focus on the differences between Nvidia's RTX series and AMD's newer Radeon 6000 and 7000 series, which have been designed with ray tracing specifically in mind.

Advantages of Nvidia's RTX Series

Nvidia's RTX series GPUs are equipped with Tensor Cores, specialized hardware designed to accelerate ray tracing tasks. These Tensor Cores significantly speed up the processing of ray tracing data and can also be used for image processing tasks such as upscaling and generating additional frames to double the frame rate in certain scenarios. Without Tensor Cores, ray tracing at high resolutions would lead to unplayable frame rates.

Example: Unreal Devkit

To demonstrate the feasibility of running ray tracing on non-RTX GPUs, users can download the Unreal Devkit from Epic Games and run their ray tracing demo. My old Nvidia GeForce RTX 570T can run this demo at playable frame rates, even without native support for ray tracing in most games.

AMD's Approach to Ray Tracing

AMD's latest series of GPUs, the 6000 and 7000 series, also support ray tracing, but their approach is different. Instead of using specialized Tensor Cores, they rely on their regular shading units to handle the ray tracing tasks. This can result in a more significant impact on frame rates when using AMD GPUs. However, this issue can be mitigated by using software like FSR (FidelityFX SuperResolution), a technology that can enhance image quality without the need for Tensor Cores.

Specific Examples of Ray Tracing Support

Several games and mods have implemented ray tracing, including:

While some older AMD Radeon RX graphics cards might struggle to run these programs efficiently, more recent cards like the RX 580 can handle them at playable frame rates. However, most games and applications that use ray tracing, such as Minecraft RTX and Quake II RTX, require GPUs with dedicated ray tracing cores. The only AMD Radeon graphics cards with these cores are the RX 6000-series, and future generations of AMD graphics cards are expected to include similar technology.

Future Outlook

Industry leaks suggest that the next-generation RX 7000-series GPUs, expected to launch in 2 to 3 months, will have significant upgrades to their ray tracing cores. These improvements should align with the capabilities of Nvidia's current RT cores, bringing AMD's ray tracing performance closer to that of Nvidia's offerings.

Conclusion

While ray tracing can be achieved on any graphics card, the performance and capabilities differ greatly between different GPU architectures. Nvidia's RTX series, with their specialized Tensor Cores, provide the best performance for ray tracing tasks. AMD's latest 6000 and 7000 series also support ray tracing, but their approach and performance are distinct. As technology progresses, we can expect more balanced performance across different GPU architectures.