I personally wouldn't run under 600 for any SLi/Crossfire setup but that's me. You may be able to run that set of gear alone on it but I'd advise looking into something with a little more output later on.
thanks for the fast reply I really appreciate it..
I forgot the board ill be using.. its p8z77 m pro..
its the first time ill be using intel and ati card..
and I really had a problem check the voltage comsumption of the parts..
please help me with this.. sorry newb here
I try to go by the rule of power needed + 200w = power supply I use. This way I know I have a bunch of headroom to add another card or a couple hard drives and some fans. Plus it's easier on the power supply if you're not pulling max or near max wattage out of it.
" Our test system is based on a power hungry Core i7 965 / X58 system. This setup is overclocked to 3.75 GHz. Next to that we have energy saving functions disabled for this motherboard and processor (to ensure consistent benchmark results). On average we are using roughly 50 to 100 Watts more than a standard PC due to higher CPU clock settings, water-cooling, additional cold cathode lights etc."
Measured power consumption R7770
1.System in IDLE = 155W
2.System Wattage with GPU in FULL Stress = 231W
3.Difference (GPU load) = 76W
4.Add average IDLE wattage ~10W
5.Subjective obtained GPU power consumption = ~ 86 Watts
So add another 86 watts to the 231 watts and you get 317 watts max load with 2 x HD 7770s. And that is on their system using 50-100 watts more than your will! HD 7770 is a very low power card.