Hi, I just purchased a GTX Titan 6GB signature superclocked. I know that macvidcards says they recommend I use an additional power supply. However, I have heard that some people have been using it without. Is this true? If I do need to use an additional power supply, what is the easiest way to do this? I found nothing concrete on what I should buy. PS: running a 4.1 mac pro with 6 core 3.33 and 48gb of ram. Any help would be greatly appreciated.