Performance and Features
Switching from the Deferred Renderer to the Forward Renderer may provide you with an increase in performance for your project.
The forward renderer can be faster than the deferred renderer for some content. Most of the performance improvement comes from features that can be disabled per material.
By default, only the nearest reflection capture will be applied without parallax correction unless the material opts-in to High Quality Reflections, height fog is computed per-vertex, and planar reflections are only applied to materials that enable it.
Leveraging these options in Epic's new VR game, Robo Recall, the forward renderer is about 22% faster than the deferred renderer on an NVIDIA 970 GTX.
The Forward Renderer works by culling lights and Reflection Captures to a frustum-space grid. Each pixel in the forward pass then iterates over the lights and Reflection Captures affecting it, sharing the material with them.
Dynamic Shadows for Stationary Lights are computed beforehand and packed into channels of a screen-space shadow mask, leveraging the existing limit of 4 overlapping Stationary Lights.
Be sure to use Unreal Engine's Performance and Profiling Tools to gauge the performance of your game when switching from the Deferred Renderer to the Forward Renderer.
You will want to pay special attention to GPU Profiling to see where GPU cost is going, as well as using the Stat Commands to aid with your profiling efforts.