Thank you chaps, that has given me a bit of insight.
As for the memory, I have on my list some Corsair Dominator Platinum "Champion" 16GB (4x4GB) DDR4 3400MHz Quad Channel Kit.
In theory the board should support from 2133 - 3866Mhz speeds, so maybe I should drop down to the lowest speed as it seems to work ok ?
Luckily my X58 PC runs just fine, so I can use that if I need to return parts and get different ones.
But, I am hoping that all will go well as I am hoping to place my order in the next day or two.
The last time I built my PC was back in November 2008 based on the Gigabyte 'Flagship' GA-EX58-Extreme board, which was also expensive, and to me it was a wise decision, as so far since then the only changes have been to the Corsair HX1000 for a HX1050. The PSU died after about 3 years and that was the replacment.
I bought two Gigabyte AMD 4870X2's by mistake, but didn't have the heart to send one back, and one of them died after a few years too, and the RMA sent me a Gigabyte 6870OC replacement. So bought another one for CF.
I kept the buying of two 4870X2's very quiet from the wife.....
But I have the itch for a new build, and the Z170X G1 gaming board really wants me to give it a home....