I have a Precision T7400 64bit running Windows 10 pro, 32 gb of RAM with dual E5440 Quad core zeons and a Quadro FX 3700 video card. The BIOS is updated to A11. I tried replacing the card with an EVGA GTX 580. I tried it in both of the PCIe 2.0 x 16 slots. It requires both a six pin and eight pin power connection. The T7400 has a 1000w psu. I used power plugs P5 (six pin) and P19 (eight pin). I also tried the P18 with the P19. No matter what I do, when I try to turn on the computer, the power button flashes amber indicating a power supply or power cable problem. I checked the voltages on the eight pin connector and they were as designed (12v on pins 2 & 3 and 3.3v on pins 4 & 8 with the remainder being COM). I also checked the P5. I am sure it is ok because I use it with the Quadro. I don't have any other plugs in the machine that provide 3.3V. What are my options, or am I missing something?
I resolved the issue. I purchased a 6 pin to 8 pin PCIe adapter and used the P18 plug with it. So, I plugged the P5 plug into the video card, along with the 8pin adapter. everything worked fine! I guess the video card needed more 12V pins, and no 3.3V.