Reflection Probes vs. Screen Space Reflections in Unity

Stealth Game & Cinematography

Reflection Probes captures the surrounding of the environment then converts and store the data in a cubemap which will then transfer the stored data to the reflective materials adding a reflection effect.

To add reflection probe, Right-click on Hierarchy>Light>Reflection probe. Now, you can expand your bounds as per your needs. Do note that, the reflection will only occur within its bounds so you need to place reflection probes wherever you need reflections.

Screen Space Reflection is a technique for reusing screen space data to calculate reflections. It is a post-processing effect which can be implemented using post-processing volume.

To add screen space reflection in your project, first add Post-processing from your unity package manager. Then go to Edit>Project Settings>Graphics and set the rendering type to deferred. Now you can add screen space reflection in your post processing volume.

Conclusion:

They both do the same thing but Reflection probe is cheap and provides only fixed reflections no matter from where you look at it so it is best to use it in low end games and mobile games meanwhile Screen space reflection provides a mush more excellent reflection at high performance cost so you should use screen space reflection where you don’t really need to worry about performance cost.