Any ideas? Video card works, but not with new PSU

[spemin]

Motherboard: MSI X58M
CPU: i7-960
RAM: 12GB Kingston HyperX
Video Card: Gigabyte 8800 GT
Monitor: HP ZR30w 30"

Summary:
Corsair 750TX + Gigabyte 8800 GT works
Kingwin STR-500 + Gigabyte 8800 GT does not
Kingwin STR-500 on another machine works, but haven't tested with 8800 GT

After reading stellar reviews about it, I recently invested in the Kingwin Stryker STR-500 PSU (fanless, 500w, 80 Plus Platinum) to replace a Corsair 750TX (making another computer with it). After installing the Kingwin Stryker, I get an error in POST: 1 long 2 short beep alert indicating that there's a problem with the video adapter (there's no onboard video on this motherboard). I've verified that all power connectors are in place, and I've tried using the both of the non-modular PCI-E connectors as well as the modular PCI-E connectors to no avail. No other devices are plugged in, and reseating the board did not help.

One clue I can offer is that if I unplug the DVI dual-link monitor cable, I no longer hear the POST error, but plugging in the cable after this does nothing. I thought I must have damaged the video card while switching the PSUs, but after giving up on the Kingwin Stryker, I reverted back to the Corsair 750TX, which worked great! Switching back to the Stryker at this point did not help. It was late at night so I gave up after going back to the 750TX one last time. When I woke up, I tried out the Stryker on a different machine that I had (AMD Phenom II blah blah, MSI Mobo, plugged into a 1080p LCD TV via onboard video), and it worked fine. I didn't have time to try the 8800 GT in this machine though since I had to go to work.

Any other stories of older PCI-E cards not working with power efficient PSUs? I realize a lot of the newer PCI-E cards have dual power connectors, whereas this one runs off a single. Could that be it?

Things I will try later:
Kingwin + AMD setup + 8800 GT + HP 30" LCD Monitor
Kingwin + i7 setup + 8800 GT + LCD TV
Ordered a non-OC'd EVGA 560 GTX, will try that tomorrow when it arrives

I appreciate any suggestions/leads that may help with this issue, and thank you all for taking the time to read this!

 

[Slugbait]

My first guess is that the PCI-E cable isn't fully seated on the PSU. Other possibilities is that the cable or the unit itself is defective.

 

[spemin]

I was thinking the same thing, but the modular pci-e cables weren't working either. When I get my new GTX 560 tomorrow, I'll be able to say with more certainty what the issue seems to be. Unless the GTX 560 is defective too, lol.

 

[jonnyGURU]

Got a DMM? Maybe there's no juice getting to the ends of those PCIe connectors. Maybe there's +3.3V, +5V, etc. power getting to the motherboard, but no +12V.

 

[spemin]

I don't have a DMM, but I should really invest in one. : )

I have narrowed down the issue to my monitor as being at least one of the reasons why my setup isn't working. Here's the monitor:
http://h10010.www1.hp.com/wwpc/us/en/sm/WF05a/382087-382087-64283-72270-3884471-4194577.html

- When I plug it in to my 1080P LCD TV using a VGA cable (via DVI to VGA adapter), it works fine with the Stryker. I'm guessing that means the PCI-E connectors are fine.
- I'm using a dual DVI cable with my monitor. I don't have any other DVI cables or splitters or anything like that to test with, but it works with my Corsair and the 500W Cooler Master PSU that was in my AMD box, and not with the Stryker. I have also tried putting the Stryker in the AMD box to no avail (rules out the i7).

Has anyone heard of anything like this? I'm just trying to exhaust all options before attempting to RMA it. I will also be receiving a GTX 560 tomorrow, and I hope it just works.