Firstly just to say the Live rendering mode seems to work very well :-) we have had numerous customers with lower end hardware (4GB or less graphics card) where they run out of dedicated video memory resulting in slow renders. This was because the "live rendering" memory was not released when you do a Final render even if you switch back to preview mode before rendering meaning it used perhaps up to double the memory it should (SPR 1131617) Now when i test and monitor with GPUZ in live redering mode this no longer happens. don't suppose there is a chance this can be back ported to 2019 though? 

Secondly does 2020 take advantage of the RTX cards Ray Trace cores for accelerating of renders and Tensor cores for accelerating AI De-noising. i believe this was the plan for 2020 but could not find reference to this. If so any stats would be good too as OEM's like Dell are just about to start selling these systems widely.