What GPU would you buy?

[crocozino]

So the AX1500i comes with 10 PCIE/CPU ports. 1 for CPU frees up 9 double headers allowing for 8 double header GPUS.

I guess that's a solution for a mobo like Z270-P with up to 8 GPU's on it.

I could even afford to throw in a 1080ti or two with 1500W to work with...

That's why people often use 2 PSUs per rig. You can get a couple of 850W units that will not only have more total power, but will also have enough cables to connect all those GPUs and risers. I personally see those powerful expensive PSUs like AX1500i as a way to power a high-end rig. Like when you run 8+ 1080 Tis or something, you could just get a couple of those 1500W units. But for 1070 Tis.. I'd just get two 850W or 1000W units (depending on the price you can get them at).

I fully agree with wacko on this, but I would like to offer one more option
you can take one 400W PSU just for mb and some risers
the main power supply unit would be server PSU from HP - 2.4KW or dell
like this one https://www.ebay.com/itm/DELL-D330T-M1000E-0Y004D-A2360P-00-Blade-Server-2360W-Power-Supply/192386659617?hash=item2ccb237521:g:qwYAAOSwAO9ZV~81
adapt it with cables  and use it.
this option will be cheaper then one 1500KW psu from corsair  + more power

[dadesu]

None from list.
If you go on nvidia gtx 1070 for mining is better to go on gainward phenix or palit yetstream, gamerock.
They have best cooling solution, very quite, and very durable. Price is almost same.