Alright thanks you, also do i need the GPU's cooling or not ?

Hi everyone, so i need to know how can i calculate the daily power cost to run 6 r9 290 and also the 6 rx 480 ?  and do i need cooling system for the r9 290 cards ? thank you 

Alright i see  thank you can someone please explain to me how can ethereum go unprofitable ?

Alright thanks the price of electricity in my country is 0.079 usd and for the rx 480 the gigabyte version is good ?

And also what is the best GPU from this list please : r9 290 , r9 380 or rx 480 because i found these for those prices : sapphire r9 290 = 250 usd , sapphire r9 380 = 280 usd ( strix version 275 usd ) and the gigabyte rx 480 8GB = 280 usd ?

Alright thank you verry much i appreciate your help, can you tell me how ethereum will go unprofitable please ?

Hi everyone so i'm new to the mining and i want to build a rig to mine ethereum but i really need help .
If it is possible to help me pick up best cards from this site to build a rig with maximum number of cards possible for an amount doest not exceed 1200 dollars for the GPU's  ( equal to 12 000 DH i'm from Morroco and i can't buy the GPU'S from outside my country it's gonna be verry expensive )
  http://www.pcpromaroc.com/epages/64433356.sf/fr_FR/?ObjectID=17465967&ViewAction=FacetedSearchProducts&SearchString=radeon
Finally i will be really thankful if someone helped me , thank you.