[SOLVED] 12 GPU PSU question

[erEx]

hello all wise people. Want to ask silly question this time. Been searching forum here and found a lots of info, just decided to ask better than make calculations and get facts wrong.
considering to build mining rig with 10 of R9 280x GPU and 2 of R9 290 GPU. My calculations make me believe that i need 4550 W of power. Could that be true?
Found a motherboard of 12 GPU spots and close to order 3x 1800 W power supply units.
could anyone be so kind and confirm my calculation or correct them? thanks in advance.

 

[kerberos_20]

your math might be wrong, recommended PSU for single GPU doesnt mean GPU will need it, its recommended PSU size for whole PC
6pin +8pin + pcie slot would be 300watts, but most bioses are limiting it to around 230 watts (to have room for ripples)
ripples happen when you gaming (every frame different GPU load), during constant GPU load (like mining) ripples should be nonexistent/minimal
so around 3kW is minimum for only GPUs (12x250watts)
if you have GPUs with 2x8pin than add 75watts per gpu

 

[erEx]

thank You, kerberos_20. great tip.