It’s impossible to be a gamer in 2023 and not have heard of Ray Tracing. It has been touted as the ‘next big thing’ in 3D graphics for the last couple years. Almost all AAA game studios seem to be heavily invested in it, with Unreal Engine 5 offering native support for the technology and Nvidia doubling down on it through their recent launch of DLSS 3.5 Ray Reconstruction.
But is ray tracing actually worth it for gaming?
Yes, ray tracing is absolutely worth it. It’s the only way to achieve photorealistic visuals with lifelike lighting and shadows in modern gaming, far surpassing the capabilities of traditional rasterization techniques. While the computational demands of ray tracing can be quite steep and may put a dent in your frame rates, the end result more than justifies the performance trade-off.
To ensure we’re on the same page here, let’s quickly look at the definition of ray tracing in the context of gaming.
- What is Ray Tracing in Gaming?
- How Does Ray Tracing Work?
- What are the Benefits of Ray Tracing in Gaming?
- What are the Drawbacks of Using Ray Tracing in Gaming?
- What Modern Games Use Ray Tracing?
- What Hardware Do You Need to Play Games with Ray Tracing Enabled?
- Nvidia vs. AMD vs. Intel for Ray Tracing – Which is Better?
- Best GPUs for Ray Tracing for Your Gaming PC
- Ray Tracing Roulette: Betting on the Gaming Revolution
What is Ray Tracing in Gaming?
Ray tracing is an advanced graphics rendering technique that mimics how light interacts with surfaces in the real world to create realistic reflections and visual effects. It enhances the quality of in-game lighting and reflections, surpassing the older rasterization techniques, such as cube maps and screen space reflections (SSR), by simulating the path of individual light rays as they bounce off surfaces in the game world.
The story of ray tracing begins with Turner Whitted, a visionary who introduced this concept in his 1980s research paper “An Improved Illumination Model for Shaded Display.” This important work laid the foundation for ray tracing’s use in computer graphics.
However, ray tracing didn’t start with gaming. Instead, it has its roots in the film industry. Pixar Animation Studios’ groundbreaking movie “Toy Story,” released in 1995, wowed the audience with its realistic-looking shadows and light effects, thanks to ray tracing. This marked a new era for computer-animated films.
The ray tracing technology took over two decades to find its place in the gaming world. Battlefield V introduced this tech with Nvidia’s RTX (Ray Tracing Texel eXtreme) line of GPUs, blending classic rasterization techniques with ray-traced refractions, reflections, shadows, ambient occlusion, and caustics. The result was near photorealistic graphical fidelity at playable frame rates.
To understand how ray tracing improves graphics, check out this ray tracing in-game comparison turned on and off in Minecraft:
How Does Ray Tracing Work?
Ray tracing works by ‘tracing’ a path from the player’s field of view (FOV). This path examines any intersections between 3D meshes, polygons, textures, etc., and the available light rays in the environment. When a ray closest to the FOV intersects with an object, the trajectory of the intersection point is used for additional calculations and acts as a reference point to save CPU resources by reducing the number of vertex calculations.
Next, the color of each pixel within the FOV is determined using a traditional shading model at the intersection point. It considers the material properties of textures and cube maps, the available light sources, and other environmental factors like mist, smoke, 3D particles, and so on.
Once the trajectory of light is calculated, rays are spawned and followed through the entire scene as photons travel in a straight line until they bounce or deflect. As a result, these rays create photorealistic light reflections and refractions from glossy surfaces like windows, water, mirrors, etc. However, computing these reflections in real-time can be quite hardware intensive. So, to speed up the process, predefined data structures like Bounding Volume Hierarchies (BVHs) are used to increase efficiency.
The downside of using the ray tracing algorithm is that these rays can create various graphical imperfections, particularly aliasing, shimmering, ghosting, and noise. Anti-aliasing techniques are used to address aliasing, with the most common being Super Sample Anti-Aliasing (SSAA). This is often paired with denoisers featuring guided blurriness filters to reduce noise and achieve a visually smooth appearance.
Moreover, Nvidia RTX GPUs also support Adaptive Temporal Anti-Aliasing (ATAA), which relies on temporal data from previous frames and harnesses the machine-learning capabilities of Tensor Cores to minimize both aliasing and shimmering. ATAA is often used alongside Nvidia Real-Time Denoiser (NRD), a hardware-agnostic API that relies on spatial and temporal data for noise reduction.
How does it differ from the traditional rasterization techniques, you ask? Let’s find out!
Ray Tracing vs Rasterization – Comparing the Two Rendering Technologies
Unlike ray tracing, a relatively recent development, rasterization has been a part of computer graphics since the early days. In traditional 3D rasterization, polygons are processed one scanline at a time instead of handling them in real-time on a polygon-by-polygon or pixel-by-pixel basis. First, vertices are converted into screen space. Polygons are broken down into fragments, with shaders applied to each fragment. This process is repeated to create the entire frame.
This technique is simple, efficient, and highly parallelable. That’s why modern GPUs feature thousands of cores, known as Stream Processors (AMD), Shader Cores (Intel), and CUDA Cores (Nvidia), specifically designed for FloatPoint or FP16 (Half), FP32, and FP64 (64-bit Double Precision) arithmetic.
On the other hand, ray tracing is computed in real-time and relies on dedicated ray tracing hardware equipped with specialized cores designed for light ray calculations. In Nvidia GPUs, RT cores are integrated at the SM (Stream Multiprocessor) level, AMD incorporates them within their Compute Units (CUs), and Intel’s Arc Alchemist GPUs have a single RT core in each Xe Core cluster.
What are the Benefits of Ray Tracing in Gaming?
Here are some of the main benefits of ray tracing in gaming:
Unmatched Lighting Effects
Real-time ray tracing offers lighting effects that traditional rasterization techniques can’t match. While cube maps, which are the rasterization technique’s answer to ray tracing, offer dynamic lighting effects and global illumination, the result often leaves a lot to be desired, and the final result looks unnatural with an artificial glow and appearance.
Because ray tracing simulates light beams similarly to real-life photons and creates realistic surface interactions, it produces ultra-realistic shadows that resemble those in the real world. In contrast, rasterization depends on shadow maps that developers manually include in their games. Although these shadows can appear realistic from specific angles, their realism diminishes when viewed from extreme angles.
Lifelike Refractions and Reflections
In addition to lighting and shadows, ray tracing provides almost lifelike reflections and refractions. Rays generated by RT mimic real-world lighting behavior. Light bounces off objects realistically, and refraction on reflective, glossy surfaces like glass, mirrors, and tiled floors is practically indistinguishable from real-life lighting characteristics.
This is one aspect where RT has a clear advantage, as traditional rasterization’s cube maps, planar reflections, and overall reflection mapping can’t come even close to RT in that regard.
Subsurface Scattering (SSS) and Translucence
Finally, RT provides real-time translucence and subsurface scattering. For instance, when an RT ray passes through a volumetric 3D object, like a cloud, it scatters multiple times within the cloud before emerging from various points. This creates a soft, translucent look for clouds, much like in real life. This feature is a major selling point for RT because traditional rasterization methods can’t match this level of graphical detail and photorealistic rendering.
However, it’s not all respawns and glory when it comes to ray tracing in gaming. The technology has its share of drawbacks, which you must be wary of before enabling ray tracing in games.
What are the Drawbacks of Using Ray Tracing in Gaming?
Here are the main drawbacks of RT:
Performance is the primary drawback of enabling ray tracing in gaming, although it has more to do with the current limitations in the hardware technology than RT itself. Unlike shader cores found in thousands on most modern GPUs, RT cores are relatively new and take up a significant amount of die space.
For example, Nvidia’s AD102 GPU, which drives the RTX4090, has just 144 RT cores compared to its 18,432 shader cores (CUDA). Meanwhile, the Navi 31 GPU, powering the 7900 XTX, only boasts 96 RT cores compared to its 6,144 shader cores (SP).
While performance at 1080p and 1440p is acceptable, even top-tier GPUs begin to struggle at 4K and beyond with ray tracing enabled.
Ray Tracing requires dedicated ray tracing hardware. While DXR (DirectX Ray Tracing), the most common Ray Tracing API, can be technically run on standard hardware, the performance impact is far too steep to make it usable, often delivering performance in single digits.
While GPUs with RT have been around for almost five years now, many users still don’t have an RT-enabled GPU. As per Steam’s latest hardware survey, the GTX1650 remains the most popular GPU among gamers, and it doesn’t offer any RT capabilities at all.
Limited Game Support
Lastly, there’s the matter of limited game support. According to Nvidia, there are now more than 470 games that officially support ray tracing and DLSS. While 470 games may seem substantial, it’s important to realize that Steam has over 50,000 games in its library, with well over 5,000 games being added each year since 2017.
What Modern Games Use Ray Tracing?
CD Projekt Red’s Cyberpunk 2077 stands out as a prime example of a modern ray tracing game, especially with its latest DLC, Phantom Liberty, which supports Nvidia’s newest DLSS 3.5 Ray Reconstruction technology. Before that, the game had incorporated Nvidia’s Path Tracing technology in the version 1.62 update.
Moreover, ‘Control’ from Remedy Entertainment is often regarded as one of the best-looking ray tracing games and was among the early adopters of ray tracing technology.
Here’s a list of some of other popular and modern games that support Ray Tracing:
- Metro Exodus
- Dying Light 2
- Doom – Eternal
- Call of Duty – Modern Warfare (2019)
- Shadow of the Tomb Raider
- Battlefield V
- Watch Dogs – Legion
- A Plague Tale – Requiem
- Hogwarts – Legacy
- Battlefield 2042
List of Old Games That Use Ray Tracing
If you’re a fan of retro games and want to experience old classics with ray tracing, here are five old games now available with ray tracing.
- Quake 2 RTX
- Portal RTX
- The Elder Scrolls III – Morrowind
- Serious Sam – The First Encounter
What Hardware Do You Need to Play Games with Ray Tracing Enabled?
GPUs matter the most when it comes to ray tracing. Make sure to buy a GPU with dedicated ray-tracing hardware. Nvidia GPUs from their Turing (RTX2000, excluding GTX1600), Ampere (RTX3000), and Ada Lovelace (RTX4000) architectures all offer support for ray tracing.
AMD GPUs from their RDNA 2.0 (RX6000) and RDNA 3.0 (RX7000) lineup also provide native RT support. Lastly, the Intel Arc Alchemist line of discrete graphics cards all support ray tracing.
While you can run ray tracing with most CPUs, purchasing a CPU with at least six cores, preferably more, is important because Bounding Volume Hierarchies (BVH) can place a significant load on the CPU, which quad-core CPUs may struggle to handle.
Does the Old GTX Lineup of GPUs Support Ray Tracing Too?
Yes, the GTX line of GPUs does support ray tracing. In 2019, Nvidia introduced support for the DXR (DirectX Ray Tracing) API for its Pascal (GTX1000) and Turing line of GPUs that lack RTX hardware (GTX 1650/1660 Series). However, these GPUs don’t offer the best RT performance and experience because of the lack of dedicated RT cores.
Nvidia vs. AMD vs. Intel for Ray Tracing – Which is Better?
Nvidia stands as the clear winner when it comes to ray tracing. This is thanks to the RTX 4000 Series’ improved 3rd Gen. RT cores, which are exponentially faster than both RDNA 3.0 and Intel Arc Alchemist’s RT cores.
Additionally, RTX 4000 GPUs offer the benefit of DLSS 3.0, or Deep Learning Super Sampling, which combines temporal image reconstruction with AI-accelerated Optical Multi-Frame Generation to boost performance substantially. Furthermore, with DLSS 3.5 on the horizon, supporting Ray Reconstruction, Nvidia GPUs are now unrivaled in RT performance.
Best GPUs for Ray Tracing for Your Gaming PC
Here are the best GPUs you can buy for ray tracing for PC Gaming:
- Nvidia RTX 4090: The halo product of Nvidia’s current Ada Lovelace lineup, this GPU offers unparalleled RT performance thanks to its 609 mm² large AD102 GPU that features 128 Nvidia’s 3rd Gen. RT cores, making it the most powerful GPU for ray tracing available today.
- Nvidia RTX 4080: This enthusiast-class product features the smaller AD103 GPU with 76 RT cores. While the performance is lacking compared to the 4090, it offers great RT performance at 1440p, often comparable to RTX 4090 running at 4K, making it a great option for 1440p gaming.
- AMD RX 7900 XTX: AMD’s flagship product featuring the industry’s first chiplet GPU in the guise of Navi 31. Although the RT performance is somewhat underwhelming, it can still compete with the RTX3090 in terms of ray tracing while delivering 33% better raw rasterization performance.
- Nvidia RTX 3060 Ti: The 3060 Ti is part of Nvidia’s older Ampere lineup. Despite not having the same raw ray tracing power as newer cards, it still delivers outstanding performance at 1080p at a highly affordable price, outperforming AMD’s mid-range options in the current RDNA 3.0 lineup. This positions it as one of the best budget GPUs for ray tracing.
Ray Tracing Roulette: Betting on the Gaming Revolution
Ray tracing might seem like a marketing gimmick on paper, it represents a significant initial stride toward creating games that reflect the real world. The technology replicates how our eyes perceive shadows and lighting in reality, and now, we finally possess the hardware capable of realizing the long-held dream of photorealistic video games.
Although the performance hit from ray tracing can still be quite steep, it’s important to remember that RT is a relatively new technology, introduced just five years ago with the launch of the RTX 2000 Series of GPUs. In contrast, rasterization has been around for decades and had plenty of time to evolve into what it is today.
Ray Tracing will mature in a similar fashion. And with the latest DLSS 3.5 Ray Reconstruction technology, we are closer than ever to achieving photorealistic video games and virtual realities.