Until reviews and benchmarks are released there is just speculation. Performance numbers from a manufacture pre-release should be taken with a grain of salt.
How much faster (in percentages) will the RTX 2080 going to be compared to the GTX 1080?
Ali Tauseef :
So far, in gaming performance the RTX 2080 is approximately 1.5x faster in most games.
Nvidia released those percentages/benchmarks in their non-definitive proof kind of way, but we can presume that would be with Real-Time Ray Tracing and Deep Learning Super Sampling enabled.
Until reviews and benchmarks are released there is just speculation. Performance numbers from a manufacture pre-release should be taken with a grain of salt.