Today, the most popular hardware for mining is NVIDIA GTX 1050 Ti.
Where is that ? It was the only card that was for sale during the start of this year ( also for a absurd price ) because no 1 bought them.
The best Nvidia is still the 1070 in my opinion, works nice on most algo's, but don't know what you mine, my 1080 Ti doesn't even make 100 $ dollar a month, so my 1070 wont make 500 in 5 months. Not even with free power, a 1080 Ti on Zcash makes around 2.78 a day, before the powercosts.
In a month or 2, a rig of 12 1080 Ti will not even break even on Zcash, welcome Asics

A 1080 Ti doesn't double a 1070, my 1080 ti run on 780 Sols / s and my 1070 does 530 Sols / s but there is a difference in poweruse, the 1080 Ti uses 225 watt and the 1070 does it with 160 watt.
If you decided to mine coins using hardware produced by amd, its more suitable for hashing algorithm Equihash used in Zcash. Also, you can mine CryptoNight used in Monero with it.
AMD and Zcash ? Zcash is team Nvidia, runs out al the AMD's

Ethereum is more a AMD game.
In my opinion, even with the new series Nvidia around the corner, Ethereum and Zcash wil be soon a no go for GPU's, they can't compete with the Asics that are coming
