@Vizour - Hey there. The 1070 is 37 to 43% faster in dx 11 than the 390x. Not 2 times. According to "17 seconds" link. Assuming games representative of entire pop of games.
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In directx 12, 390 similar to 1070 possibly. Evidence:
https://www.computerbase.de/2016-03/hitman-benchmarks-directx-12/2/
However a lot of FAKE NEWS around these days! In a few years when more data, then I will believe for sure.
I may upgrade to 1070 reluctantly as my 390 is having technical problems.
Cheers.