for SA 1.45 V was the safe limit for 6th gen, but Intel's 14nm has improved a lot, so up to 1.65V is fine since Coffee Lake.
My chip is delidded and has a Supercool computers direct core mk6 block fitted to it with conductonaut. Under load in realbench Vcore droops to 1.43V under LLC6 and temps stay below 70C for all cores, so should be fine, no?