toniochen
I am interested in acquiring a EVGA GeForce GTX 1070 Ti FTW2 GAMING but I am a total noob hence I am very confused about 2 things : PSU power required and PSU connector. 
I currently have the following GPU and PSU:
-1 x Gigabyte GeForce GTX 970 OC 4GB 7.0GHZ GDDR5 2xDVI HDMI DisplayPort PCI-E Video Card
-1 x Corsair CS550M CS Modular 80 Plus GOLD-RATE 550W 12V Power Supply
 
1) How do I know if I can connect this new GPU to my PSU ? I see people talking about 8 pin or 2 * 6+2 etc...I have attached pictures of my current connectors. Seems like 2 x (6+2) to me. no ?
2) Is the 550W enough for that card ?
 
Thanks,

Hello and welcome to the forum. You're fine. Those are the 6+2 PCIe power connectors which plug into the GPU. The min recommended power supply is 500 watts

You should probably be good with the CS550M..Those 6+2 pin PCIe supplemental power, or PEG (PCI Express Graphics) connectors supply additional wattage over and above the 75W a card can draw from the PCIe x16 slot itself, per PCI-SIG specs..The 6+2 pin connectors can function as either a 6-pin (with the 2-pin part left hanging) or an 8-pin (with the 2-pin part added to the 6-pin part) connector, as needed.

A graphics card can draw up to 75 additional watts from a 6-pin and up to 150 additional watts from an 8-pin, per PCI-SIG specs.

EVGA says the "Minimum system power requirement based on a PC configured with an Intel Core i7 3.2GHz processor" for a GTX 1070 Ti FTW2 is a 500W PSU..That's generally speaking.

You can estimate your overall system wattage requirement using the OuterVision Power Supply Calculator or the EVGA Power Meter and see a recommended PSU..The OuterVision Calculator is much more detailed..If you use the EVGA Power Meter, you'll recieve a 10% discount code in your email just for using it that's good for 30 days in the EVGA store only in the US.

EVGA GTX 1070 Ti FTW2 Product Page
EVGA GTX 1070 Ti FTW2 Spec Page