https://www.pcgamer.com/watch-these-guys-try-to-guess-if-ray-tracing-is-turned-on-or-off-in-battlefield-5/

One of the main selling points of Nvidia's GeForce RTX series graphics cards is the prospect of real-time ray tracing. In games that support Microsoft's DirectX Raytracing (DXR) API, the RTX series enables more realistic reflections in ray-traced portions of a scene, but is it a noticeable improvement over having the feature turned off? That's what UFD Tech aimed to find out in a blind test.

The four guys responsible for the UFD Tech channel on YouTube each took turns playing Battlefield 5 with RTX enabled and disabled, but without seeing the setting (credit to HardOCP for the heads up). They then noted which experience they thought RTX was on, and which one it was off.