then turing is hybrid RT hardware? like RDNA2 will be.
I'm not sure what that term hybrid means... Ray-tracking is just an algorithm like rasterization... both can be used to render graphics... both uses shader units to be rendered... so in both cases you use Stream Processors.
The different is that Ray-tracking is too heavy to be processed (in fact it has way way way more processing calcs than rasterization)... so to speed up some calcs for ray-tracing nVidia added a hardware unit specialized in speed up these ray-tracking calcs... when there is ray-tracking calcs that can be speed up by the RT core it will run in the RT core instead the SP unit... that way the that specific calc will be done faster.
What ray-tracking calcs are fixed in the RT core I don't know... nVidia didn't disclosed that too... I can only guess that that RT core has some fixed functions/maths that are most used in ray-tracking render to speed up the processo but it doesn't have all the RT functions/maths... there not found in RT core are done by the SPs like in any previous GPUs.
If hybrid is that then nVidia solution is hybrid.
In simple terms... let's say the ray-tracking algorithm has 100 most used calcs... from these 10 most used calcs are speed up by RT Cores while the rest runs in the SPs in Turing.
* Remember I'm guessing here... I don't know how what instructions/calcs are fixed in the RT unit but I believe it is less than 10% of ray-tracking tasks *