AMD GPU Comparison of FSR 4 and DLSS 4 Ray Tracing Performance

Ray reconstruction enhances lighting consistency across complex scenes by improving reflection stability and global illumination accuracy

Hardware by Godrics01 on Nov 27, 2025

FSR4 is a substantial improvement to AMD's upscaling solution. It reduces ghosting and improves detail for finer geometry, particle effects, and lighting. However, there is one area where FSR4 still lags behind DLSS: ray tracing. The lack of a dedicated denoiser like ray reconstruction leaves it at a disadvantage in ray-traced and path-traced games compared to DLSS4.

Traditional ray tracing in games uses only a single ray per pixel, or even fewer, to calculate scene lighting, which is far from sufficient to accurately represent lighting. Denoisers fill in missing lighting data by looking at surrounding pixels and neighbouring frames.

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By combining spatial interpolation and temporal accumulation, they clean up the scene and produce the ray tracing seen in current gaming. Much like FXAA, TAA, and temporal upscaling, this is an approximation and often results in loss of lighting data, leading to blurring and muddying of reflections.

Denoisers

Denoisers fill in missing lighting data by analysing surrounding pixels and frames. We see the results of this process in modern games, but it still introduces approximations that cause blurring and muddy lighting, most evident in reflections. When you look closely at those reflections, the limitations of traditional denoisers become apparent.

Ray Reconstruction

Ray reconstruction removes blurring by rejecting invalid pixels, thereby substantially improving detail, especially colour detail in reflections. Most ray tracing pipelines have dedicated denoisers, but when upscaling is used with ray tracing, the ray samples are reduced from one ray per pixel to two to three pixels per ray. For these scenarios, a dedicated denoiser for the upscaler becomes essential.

When comparing FSR4 with DLSS4 alone, FSR4 delivers nearly identical quality even at the performance preset. We see a different result when ray reconstruction is enabled. Ray reconstruction overhauls reflection quality and improves global illumination detail.

The impact becomes more apparent with path tracing, especially in glossy and semi-glossy reflections. Colour detail retention improves with ray reconstruction.

FSR4 vs DLSS4 With Ray Reconstruction

Ray-traced reflections with FSR4 appear noisier, while DLSS4 with ray reconstruction produces more stable reflections. If you focus on brown tiles, you notice improved shadow detail and enhanced geometric definition. With path tracing, these differences become even more obvious.

DLSS4 retains more colour-saturated sunlight detail, blending it with surrounding light sources to produce a more balanced lighting response. Ray reconstruction becomes effective for colored light bleeding as well.

The light bleeding effect on roads and pavements appears more precise. Ray reconstruction also preserves more shadow detail from reflections.

Path Tracing Differences

Even without path tracing and sticking to ultra-quality ray tracing, the differences between FSR4 and DLSS4 with ray reconstruction remain significant. Ray reconstruction improves ambient shadows, light bleeding, and multibounce global illumination.

Diffused GI and reflections also benefit from ray reconstruction. Shadows become deeper and more uniform while illuminated areas appear more consistent.

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Performance Mode Comparisons

When we compare FSR4 performance mode and DLSS4 performance mode without ray reconstruction side by side, the ray-traced lighting quality appears the same. However, DLSS4 delivers better geometric detail in certain rare cases.

Muddy textures show more detail with DLSS, and the same applies to objects like mattresses and stalls. Once ray reconstruction is switched on, the overall amount of light in the scene increases, improving reflections and shadowing. With path tracing, shadows become more detailed and fuller.

Ray reconstruction improves lighting resolution by sampling and accumulating more rays, resulting in more uniform illumination. FSR4 can appear noisier with visible artifacting on darker surfaces, while DLSS4 remains smoother. Some shadows are also missing on the FSR4 side. Coloured light bleeding becomes more evident on surfaces such as muddy floors.

Vegetation and Diffuse Lighting

For vegetation occluded from direct light, DLSS provides superior illumination even without ray reconstruction. With ray reconstruction enabled, the global illumination quality and accuracy improve further. You see lighting becoming more precise, with shadows closer to the roots, while illumination becomes brighter near the leaves and stems.

FSR4 shadows appear more blanket and less defined in comparison. Ray reconstruction again produces more accurate lighting in scenes where shadow gradients matter. Shadows appear darker near stalks and more illuminated near leaf tips.

Interior and Low-Light Scenes

Dimly lit interior paths traced scenes that look similar at first glance, but ray reconstruction retains more colour when viewed closely. The overall amount of light in the scene is increased, producing deeper, more uniform shadows.

In indirectly lit outdoor scenes, ray reconstruction substantially improves the quality of ambient shadows, many of which are lost on the FSR4 side.

AMD, GPU Comparison, FSR4 and DLSS4, Ray Tracing Performance, NoobFeed

Final Thoughts

In scenes with natural lighting, ray reconstruction alone is not always transformative. With path tracing, it enhances multibounce diffuse lighting in foliage and shadowed areas. FSR4 can lead to blurring of grass and foliage, while ray reconstruction retains structure more effectively.

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