** so this is what bitmain has on thier page
https://shop.bitmain.com/product/detail?pid=000201809111803105065Lb6UvUc068AAPW3++
The APW3++ can deliver a maximum power of only 1200W if it is connected to a 110V mains power supply. To obtain the rated power of 1600W, the APW3++ must be connected to a 220-240V
APW7"The APW7 can deliver a maximum power of only 1000W if it is connected to a 110V mains power supply. To obtain the rated power of 1800W, the APW7 must be connected to a 220-240V"
so if you are using 110 vs then you should get the APW3++ which give you 1200w . if you are using 220v then you should get APW7 as it gives you 1800w instead of 1600w.