Dual sli, possible?

I have a system built with a 750w psu. its a Corsair CX 750W 80 PLUS Bronze Certified ATX12V Power Supply.
so my question is, is it possible/safe to do dual sli with 2 Gigabyte geforce GTX 670 4GB videocards?

I have had this problem where I dont know is my psu enough and there are alot of wattage calculators and they give different wattages. I kinda would wanna know is it possible or should i upgrade to ie. 850w psu? Thanks c:

CPU: AMD FX-8350 4.0GHz,
CPU Cooler: Antec KUHLER H2O 920,
Motherboard: Asus Crosshair V Formula-Z,
Memory: G.Skill Ripjaws 16GB (4 x 4GB) 1600mHz,
Storage: Seagate Barracuda 2TB 3.5",
Video Card: Gigabyte GeForce GTX 670 4GB,
Case Fans: 3x Cooler Master Megaflow 110.0 CFM 200mm,
Power Supply: Corsair CX 750W 80 PLUS Bronze Certified,

Yes, 750W PSU is fine for a pair of 670s