Friend.. it's up to you to take the advice. I said what i would do. Because I make extreme high performance machines, some with custom built graphic cards costing above 5000$. I am aware of the power consumptions when overclocked and when graphics cards are pushed to the limits. FYI I maintain systems with more than a 1000 cores.
The system will work with 750W. How much power the H100i cooler alone takes? You will be surprised.
If you read the Gigabyte RTX 2070 documentation you will find that running at base frequencies it does require a minimum 650W PSU.
What happens if you decide to add more hardware, say another graphics card. If you can afford have some flexibility.
Hope this explains.
