PSU requirement for GTX 660ti SLI

Cazral

Honorable
Dec 15, 2013
6
0
10,510
Here's my rig:

Asus GeForce 660ti OC 2GB (factory OC)
Intel i7-3770k
Corsair Vengeance (8GB RAM)
SSD 240GB
HDD 2TB
Corsair GS600 (600w PSU)

So I'm getting another 660, and my question is if my 600w PSU will suffice or not, or if I should get an upgrade. Thoughts?