I wouldn't buy any Pascal based Nvidia cards for mining Ethash.  Nvidia Pascal cards are no where near as efficient today on Ethash as the Polaris cards despite pulling over twice the power and running much hotter than AMD Polaris cards. Pascal 1070/1080/108Ti cards have the DAG file size limit bug where they lose hashrate every month from the growing DAG size. Nvidia never patched it, now even with a 1080Ti you might get ~45 MH/s instead of the 55 MH/s+ you originally got. AMD quickly developed the blockchain drivers to address the issue before it escalated and continues to implement it in their current drivers with compute mode. Many large mining farms that were started during the 2017 bull run still in operation are still using Polaris cards.