hd 2900xt power question :( (and 8800gts 320mb bootleneck)

hi friends from toms hardware, i have 2 question that i know u will answer me (like u did in the past).

a) the hd 2900xt uses 2 pci exp power conectors, but have not a power suply with pci express conectors, so i see that in the accesories of the gecube card come with 2 power converter (molex to pci exp). in the past i used a x1800xt and that card had a converter too, with one molex to power a pci express. in this moment i have a 8800gts 320mb and it uses an converter, but requires two molex to power only one pci express, so the question is: I need 2 molex to power the converters to pci express (like the x1800xt) or 4 molex (like the 8800gts, but since it requires 2 pci express it will be 2x2=4) for a hd 2900xt? (the asus model had the converters like the gecube. the converters of the gecube are like the ones from the x1800xt (1 to 1) but the asus model´s are like the 8800 (2 to 1) so thats confusing) and also my question is confusing

b) if i have an 8800gts 320mb what cpu will be the minimun to avoid a cpu bootleneck? (i have an atlhon 3800+ single core) and for the hd 2900xt?

thank u beforehand, i know my questions are long, but i know i will help me