i have never said it will not work....... 780 requires a 42amp on 12+ rails so if your psu have 42 or more amps then it will work, just make that sure or u may either damage the card or psu or other stuff and one more thing putting the card on and running the pc dosent makes it work the test is when u play gfx intense games and the gpu comes under load it will draw much more power than normal then u may face restarts and black screens........
and that card u have shown to me just now is 10.5 inches in length i have checked if ur case has 9 inches of card clearance , there is no way it could fit.....