I would like to ask the encoder engine of the RTX 2080. I did the comparison test. In the same parameters, the RTX 2080 Encoder occupancy rate is twice that of 1070Ti. Is it because the RTX 2080 has only one encoder eigine?

It looks like this is true, yes. The new consumer RTX cards would appear to only have one NVENC.

Yes, RTX 2070, 2080, 2080 TI has only one NVENC engine, there is no support matrix for RTX models, so nobody knows if Quadro RTX 5000/6000 will have 1,2 or 3 engines…