6600GT PCI-X asking for power connector

[Mastocator]

I have recently got another 6600GT to put with one i already have so i can run it SLI. I bought it second hand so i installed it alone in the computer first to test it out and see what kind of OC results i can expect from it. After windows loads to the desktop i get an "NVidia Sentinal" Power indicator warning, it says there isn't sufficent power to the card and it will be underclocked for stability and damage prevention. Says to connect the external power source to the card, it doesn't have one, such is the case with the pci-x cards.
I'm ruling out any other system component as the problem, since my other 6600gt runs fine and doesn't get that error.
Any ideas to the cause, and any ideas for a solution?

My system spec:
Asus A8N-SLI Deluxe
AMD 64 3500+ 2.2 @ 2.5ghz (11x227) 90nm Winchester Core
2x512 Corsair XMS 400 @ 455mhz DDR 2.5-3-3-8 1T
TTGI PSU 600w, 30A on the 12v rail
Both are eVGA 6600GT 128mb PCI-Express cards

[Roadhog]

are you sure it doesnt have one?

[Scunner]

Yeah, the 6600GTs have a header on the board where a power connector would go, but no actual adapter.

Try plugging in the EZ-Plug on your motherboard with a 4-pin molex if you haven't already.

[Mastocator]

Ya, it doesn't have one.

the EZ plug is connected also.

[Roadhog]

what psu do you have?

[jAkUp]

Which drivers are you using?

[Mastocator]

what psu do you have?

TTGI 600w, 30a on 12v rail

[Mastocator]

Which drivers are you using?

ForceWare Version: 81.95

My other 6600GT works fine in the system, though. So I don't feel its any other hardware.

Anybody had any luck getting a replacement card? (regardless ATI or nVidia)