PSU Wattage Help

[GamingRealist]

So im upgrading my PC and several other things. I'm also wondering how much Watts does the new PSU have to have?

Specs:
AMD Phenom II X4 965BE 3.4GHZ
GTX 670
8GB DDR3

I've heard that you don't buy cheap high-watted PSU's, as you can get high quality ones that are around 400-500w.

Thanks.

 

[GamingRealist]

What about if i was going to get a AMD 7950? Would it cut it down to a 500W?

 

[GamingRealist]

Okay lads, TY for help!