nice man! i will give a shot with 4x 1070 too...
how much nexus did u receive for each block?
block is 12.86NXS now and slowly declining.
You need at least 4 core CPU for 4 Nvidia cards.
If Nexus wallet is running on the same PC as miner, you need i7 CPU, otherwise, your wallet starts to lag and you will never find any blocks.