R9 390/ 970 Watt?

[babo22013]

I'm considering to buy a R9 390 or a 970, and would like to know how much watt the PSU to have.
I'm using a i7 4790k
and what are the pros and cons for these cards

 

[RababNoor]

Any 650W Good Quality PSU [Tier 1 or Tier 2] is enough
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html

R9 390:
+8GB Vram
-Power Hungry

GTX 970:
+Better Driver
+Less Power Consumption
-3.5GB Vram

 

[maxalge]

I'm considering to buy a R9 390 or a 970, and would like to know how much watt the PSU to have.
I'm using a i7 4790k
and what are the pros and cons for these cards

500w + for the 970


650w + for the 390


tier 1 or 2 unit from the list posted of course