Hardware sleuths did manage to draw some comparisons based on some results AMD shared from the Microsoft DXR SDK tool called Procedural Geometry. VideoCardz writes it looks like AMD's Navi 21 GPUs are slower than NVIDIA's Ampere when looking at ray tracing:
This means that GeForce RTX 3080 is around 33% faster than Radeon RX 6800 XT in this particular benchmark. OF course, there are few things that need to be taken into the account such as the testing platform and DXR benchmark resolution (AMD did not clarify, hence we used default).For better benchmarks we'll probably have to wait 2-3 more weeks.
The stock GeForce RTX 3090 has a framerate of 749, according to the screenshot posted by Hassan Mujtaba (Wccftech). This means that RTX 3090 is 59% faster than AMD RX 6800XT in this DXR test.