Video card prob/new system

Just built a new pc

athlon 64 3000+
DFI Lanparty UT nforce 250gb moboard
2x 512 meg Corsair XMS PC 3200 ram
80 Gig SATA HD
Chaintech Geforce 5900 XT 128 meg
Nec DVD+r+rw
phillips dvd+rw
420 Watt PSU

problem is when windows boots up I get a pop up sayin my vid card is not receiving enough power and to prevent system malfunctions it will downgrade my vid card performance. Basically I get more performance out of my Radeon 9600 then I do out of my 5900XT. It's my understanding that the Geforce FX cards run at 1.5v, my bios shows my agp slot getting a consistent 1.52v. Any idea what I can do to resolve this? I will say I have not gotten the newest nvidia drivers, im using the ones that came with the card, (im on dial up, 17 meg download is unlikely to complete) and not sure if this would actually fix this problem. Any help is appreciated.

 

oh i noe this!

your graphics card will have a little plug on it somewhere with 4 contacts on it
plug a 4 pin molex plug into that, it should work