Question Is 400w PSU enough for a GTX 970/980?

[Nenadinho]

Hello,

I would like to test a GTX 970 or GTX 980 on my PC, but I don't know if my PSU has enough power.

My PSU model is bequiet system power 8 (400w), My CPU is I7-7700 (Non K)

What do you guys think?

 

[COLGeek]

The minimum PSU wattage for a 970 is 300w and for a 980 it is 450w. I would prefer a bit more headroom, if me, with both of those. Like, at a minimum, a quality 500w PSU.