Help configuring ASRock P67 Ext6 + NVidia Quadro K4000

[vstokesjr]

Motherboard: ASRock P67 Extreme6
Graphics Card: PNY NVIDIA K4000 Quadro
Power Supply: Corsair 750TX
CPU: Intel i7-2600K
RAM: 16 GB

Problem: Won't POST when K4000 installed.

I am upgrading my working PNY NVIDIA 600 with a brand new PNY NVIDIA K4000. The computer works fine when the 600 installed but when I replace it with the K4000 the computer doesn't POST correctly. I have confirmed the K4000 works as I installed it into another computer and it boots. I can't figure out why it won't boot with the ASRock P67 motherboard. Here is what happens:

1) Power On
2) AMI BIOS (latest available from ASRock - but not the beta)
3) POST step (lower right-hand corner) cycles and the pauses at step B2.
4) After 60 seconds, POST proceeds but then a blank screen with a blinking cursor.

That's it. Won't go any further. If I re-install the 600 graphics card the machine boots just fine.

Any ideas?

 

[Someone Somewhere]

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems

What brand/model is the power supply, and do you have all the PCIe power sockets on the card connected?

 

[vstokesjr]

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems

What brand/model is the power supply, and do you have all the PCIe power sockets on the card connected?

Power Supply: Corsair 750TX

Yes, the PCIe power is plugged in.

However, we stumbled onto something interesting. The machine will not boot with just the K4000 installed however, if the 600 AND the K4000 are installed then the machine will boot. The monitors (2) are plugged into the K4000 and working but we have to leave the 600 installed for the machine to boot. Not sure why this works.