Ray tracing turns lighting in games from a clever fake into actual physics simulation. Reflections that match what’s in the room. Shadows that soften correctly with distance. Global illumination that bounces light around corners. It also tanks frame rates if your GPU isn’t up to the job. Here’s how it works and what the cost really looks like in 2026.
The short answer
Ray tracing simulates light by casting virtual rays from the camera into the scene. Each ray bounces off surfaces, picks up color, and reports what hit it. The result is realistic lighting, reflections, and shadows that don’t need pre-baked tricks.
The catch is math. A 4K frame at 60 fps means roughly 500 million rays per second at minimum. That workload runs on dedicated RT cores in NVIDIA cards, ray accelerators in AMD cards, and similar hardware on Intel Arc. Without those units, ray tracing crawls.
The longer explanation
Classic rasterization, which has powered games since the 90s, projects 3D triangles onto a 2D screen and uses tricks to fake lighting. Cubemaps for reflections. Shadow maps for shadows. Screen-space ambient occlusion for contact darkening. Each trick works in a narrow case and falls apart in others. Reflections show the wrong room. Shadows clip through walls. Global illumination is baked into the level at design time and can’t react to player flashlights.
Ray tracing fixes all of that by running actual light transport. From each pixel on your screen, the GPU traces a ray backward into the scene. It hits a surface, samples the material, then casts secondary rays toward lights, reflections, and bounce surfaces. Each bounce is a real physical interaction, so the result matches what real light would do.
Modern engines don’t trace every pixel fully. They use hybrid pipelines. Rasterization handles the base image, ray tracing handles only the effects that benefit most: reflections, ambient occlusion, shadows, and global illumination. That’s why a game like Cyberpunk 2077 can run path-traced lighting at all without melting the card.
Why it works this way
RT cores on the GPU are purpose-built for one math operation: bounding volume hierarchy traversal. That’s the algorithm that figures out which triangle a ray hits without checking every triangle in the scene. On older cards without RT cores, that work falls back to the shader cores, which weren’t designed for it and take roughly 10x longer.
The newest Blackwell architecture in the RTX 5090 and 5080 pushes RT throughput further. Fourth-generation RT cores handle more rays per clock and add hardware support for opacity micromaps, which cut waste on transparent surfaces like foliage. Real-world impact: heavy ray-traced scenes that ran at 35 fps on a 4080 now hit 55-60 fps on a 5080.
Denoisers do the rest of the heavy lifting. Tracing enough rays per pixel for a clean image would need thousands per frame. Instead, engines trace just a few and use AI-trained denoisers to fill in the noise. The result looks clean even though the underlying ray count is tiny.
When you would want this
Single-player narrative games benefit most. Cyberpunk 2077, Alan Wake 2, Hellblade II, and Indiana Jones and the Great Circle all use ray tracing in ways that change how the scene reads. Wet streets reflecting neon signs. Light pouring through stained glass. Caves where your torch is the only source. Those moments don’t work without it.
Competitive multiplayer is the opposite case. In Valorant or CS2, you want 240+ fps and zero distractions. Ray tracing costs frames and adds visual noise. Most pros leave it off.
The middle ground is creator and modder content. Path-tracing mods for older games, like RTX Remix for Half-Life 2 RTX or Portal RTX, take legacy titles and rebuild them around full ray tracing. The visual jump is dramatic when the original art holds up.
Common misconceptions
“Ray tracing means every game looks photorealistic.” Not really. The art direction still matters more than the lighting tech. A flat-shaded indie game with ray tracing still looks flat-shaded. What changes is how light behaves, not the underlying assets.
“You need a 5090 to run ray tracing.” False. An RTX 4070 or 5070 runs ray tracing comfortably at 1440p with DLSS. AMD cards from the RX 7000 and 9000 series handle it too, though with a bigger performance hit than NVIDIA in heavy scenes. The 5090 only matters if you want full path tracing at native 4K.
“DLSS is the same as ray tracing.” They work together but they’re separate. DLSS is upscaling. It renders the game at lower resolution and uses AI to fill in the rest. Ray tracing is the lighting model. Most modern setups use both, with DLSS clawing back the frames ray tracing costs.
Frequently asked
How much fps do you lose with ray tracing on?
It depends on the game and the level. Light RT effects like RT shadows in Resident Evil 4 cost around 10-15%. Full RT reflections plus global illumination in Cyberpunk drop frames by 40-50% native. Path tracing without DLSS can cut frame rate by 70%.
Do I need DLSS or FSR to make ray tracing playable?
On most cards, yes. DLSS Quality or FSR 3 Quality typically restores enough headroom to hit 60+ fps at 1440p with heavy RT on. Without upscaling, only flagship cards run heavy ray tracing at native resolution.
Why does ray tracing look noisy in some games?
Bad denoising. If a game traces too few rays and the denoiser is undertuned, you’ll see grain in shadows and reflections, especially during fast camera motion. Patches usually clean this up, but it’s a common launch-window complaint.
Will ray tracing become mandatory?
It’s starting to. Doom: The Dark Ages, Indiana Jones, and Star Wars Outlaws all require ray tracing hardware on PC. Older GTX 10 and 16 series cards can’t even launch them. Expect more required-RT titles through 2026 and 2027 as developers stop maintaining the rasterization-only path.
