Titan V vs 1080Ti vs 2080Ti

Since I want to buy a new computer.
I wonder how fast of titan v using tensor cores compared to 1080ti.
Current comparision shows that titan v is only 50% faster than 1080ti.

But titan v has 110TFLOPS, I wonder how soon it will be full potential (10x faster than 1080ti)

If it is just a gimmick, I would like to buy 2-4 1080ti.

In term of current pytorch framework