not correlated in this respect means you have full additivity?
I want to start with 3 GPUs. Would you recommend me to buy a 1500W PSU right away or buy a 1000W now and 500W later in case I want to upgrade?
For me it's better to by even 3 gpus..for instance
850w, 750w, 750w this is what i need for 6x r9 290 oc im my case..
that's 300 euro in my country...
1x 1200w power supply cost 300 itself atm!!
so i would just go for few smaller ones. i like thoose Corsair CS750 casue they are cheap and have 91% efficiency and You can easly hook up 2x r9 290 to it...850 i use for 2x r9 + mobo + cpu.
All about costs. I use two corsair AX 760 for a machine.