The GTX 1660 SUPER is the first "SUPER" Turing without ray-tracing support. The card reportedly uses the TU116-300, the same as the GeForce GTX 1660, and has 1408 CUDA cores.
The new thing is that the GTX 1660 SUPER supports GDDR6 memory, the card sticks with a 192-bit memory bus but its 14Gbps 6GB GDDR6 memory offers 336GB/s of memory bandwidth, quite a bit more than the 192GB/s offered by the 8Gbps 6GB GDDR5 found on the regular GTX 1660.
Pricing is expected to be $229. That's $10 more than the regular GTX 1660 and $50 less than the GTX 1660 Ti.