I couldn't find much on the web regarding comparisons between 1660 and 3060 in terms of video encoding ... but in the results I found, the 1060 was NOT slower. Why would it? ... Nvidia put the same encoding hardware on the newer cards.
In other 3D related applications the 3060 clearly beats the 1660
No offense, but I don't care what you couldn't find on the web. In REAL LIFE USE, the RTX 3060ti performs much faster than the GTX 1060
encoding videos. The GPU architecture has completely changed as well as the introduction of Tensor cores and Ray Tracing Cores that are not present on the 1060.
The 1060 is also PCIE 3 while the 3060ti is PCIE 4 compatible. AI software also runs considerably faster...dropping an operation on the same video from
7 hours of processing time to just over 3 hours with the 3060ti.
And...while the CODEC is still called NVENC, it's 2 generations higher in development.
Even considering the difference between a 1060 and a 1060ti, you are looking at a 35% improvement.
I think you need to consider all hardware combined. If I pulled a 1060 out of a 5 year old computer and slapped in a 3060ti, I wouldn't expect a great deal of
a performance boost, but considering all the improvements, I would expect moderate improvements.
I'm not running a 5 year old computer though.
Motherboard: ASROCK X570 Taichi Razer Edition
Processor: AMD 9 5950X
GPU: ASUS NVIDIA GeForce RTX 3060 Ti V2 Edition 8GB GDDR6 PCIE 4.0
Memory: Corsiar Vengence Pro 128GB DDR4 4000
Boot Drive: Samsung 970 EVO Plus 2TB M.2 NVME
Scratch Drive: Samsung 960 EVO 1TB M.2 NVME
Search...3060ti encoding video improvements for more detailed info.
AND as I stated...no offense intended. I believe the system as a whole makes a big difference.