My GTX 1060 6G got to
387h/s with i7-2700k @4.6Ghz in Linux Mint 18.3
But it doesn't get near
360h/s when i use Ubuntu 18.04 !
http://oi67.tinypic.com/1072y42.jpgBy the way,
in the screenshot you can see that the miner use only 1 thread, it does not profit from all cores

i think it's not optimized well for multi thread.
PS:
Mint use driver 384.113 with Cuda 8
Ubuntu use driver 390.59 with Cuda 9
have you tried the 2700k on stock clocks? or more cards? id be intrested to know how an older i7 scales with 4 cards