peak power consumption for that 780 is 196w http://www.techpowerup.com/reviews/MSI/GTX_780_TF_Gaming/24.html
unless you have a 9xxx series amd cpu your cpu/mem/chipset tdp will be less than 200w
this is 400w
your psu supports 636w on its 12v rail so it will handle your system and have plenty of head room. seasonic is a very good choice as well
peak power consumption for that 780 is 196w http://www.techpowerup.com/reviews/MSI/GTX_780_TF_Gaming/24.html
unless you have a 9xxx series amd cpu your cpu/mem/chipset tdp will be less than 200w
this is 400w
your psu supports 636w on its 12v rail so it will handle your system and have plenty of head room. seasonic is a very good choice as well