ultimate gaming computer !

[Meo_05]

Hi ! i have a few questions for you guys please help!

i actually have a gaming computer wich is working really great ! but i would like in the future add another ati radeon HD 6990 but.... do im gonna have power enough to run it ? does my cpu is going to bottleneck it ? my rams are ok ?

here are my specs:

CPU: intel core 2 extreme 3ghz overclocked at 4ghz
mobo: asus p5e3 deluxe crossfire ready 2X pciexpress 2.0
rams: 4x2 gb= 8gb DDR3 1333mhz
psu: antec truepower quattro 1200 watt 80 plus certified
graphic card: XFX radeon HD 6990

so does it gonna work great with another 6990 ?
or im not gonna have power enough to run these 2 6990 ?
on the AMD web site they said that we need 1200 watt 80 certified power supply to get maximum performance but i doubt cause of my overclocked cpu that is actually takes a lot of power (1.52 volts)...hope its gonna be alright.... i dont wanna buy another poweer supply these are so expensive