just an FYI - the seasonic is a good PSU but honestly there is no sense going for 620 watt PSU that can't do a dual card setup (it has one 6 and one 6+2 pin power connectors) i have the same connections in my antec and i keep kicking myself because its slightly too big for one card (i think of it as nothing to use a molex adapter for my physx card)
i really recommend getting a more efficient PSU even though it a little lower in wattage:Rosewill CAPSTONE-550 550W Continuous @ 50°C, Intel Haswell Ready, 80 PLUS GOLD, $84.99
Save: $15.00 (15%)
works out about the same CAD.
on a side note i would SLI using 2 molex adapters for a 760 setup for that or my 620 watt but i wouldn't recommend it to others - i am crazy like that