How big a wattage do I need for new GPU and OCing?

[Foedragon]

I'm upgrading to a GTX 980 and also going to be OCing my CPU, nothing crazy, and need some advice. I know my 650 watt PSU will be pushing it, so will I be ok with an 850w or should I bite the bullet and go 1000w? This will be my last upgrade for this rig so the following specs will be final. Thx for any input;

CPU - i5-4670K
CPU Cooler - Cooler Master Hyper 212 EVO
Motherboard - MSI Z87-GD65 Gaming
Memory - G.Skill Sniper Series 16GB (4 x 4GB) DDR3-1866
Storage - Samsung 840 EVO 120GB 2.5" SSD,
Samsung 850 EVO-Series 250GB 2.5" SSD,
Seagate Barracuda 1TB 3.5" 7200RPM,
Western Digital Caviar Blue 1TB 3.5" 7200RPM
Video Card - EVGA GeForce GTX 980 4GB Superclocked ACX 2.0
Optical Drive - Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer
OS - Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit)

 

[Suztera]

What 650W?
A decent 650W is fine.

 

[Dark Lord of Tech]

If you have a decent 650w it will run it easily , could also run on a solid 550w.