ok so i have a compaq sr1650nx and i'm finally throwing in a video card. the card i want is the ASUS EAH4870 DK TOP. it requires at least a 500w ps with 2 x 6pin. my mobo is A8AE-LE and compaq chat isn't great i was told that i can only use up to a 450w ps but i don't think that is the case. is it? and what is the main connector i need? 20 pin? 24 pin? 20+4? somebody plz point the way to a power supply that would work with my mobo and the gpu i want plz plz plz =) thanks