Hello, I have an early 2008 MacPro with a 980W power supply. I am wanting to get two Radeon 7950's. Can my Mac Pro run two of these cards with the current power supply? I currently have the Nvidia 8800 and it only has 1x 6 pin connected to it, but the 7950 requires two 6-pin each. I believe i would need a slitter. Is this correct? I appreciate your time, and any advice or help you can offer. Thanks!