Gigabyte GA-Z77X-D3H no display on GB HD 7870

[o0Raven0o]

Hi forum, thanks in advance for any help you may be able to offer.

Having a bit of a problem with a new build (see specs at foot of message). I have an HD 7870 connected to an LG E26360 monitor (via DVI cable) and when booting I get one long and three short beeps from the system and no display. If I then reboot with the internal graphics card connected I can get in to Windows 7 but, the 7870 does not show up in the device manager.  

Here is what I've tried:

• Set the primary display to be PEG.
• Disabled the onboard VGA.
• Shifted the card into different slots.
• Tried different RAM configurations, i.e. different slots, 1333mhz and 1600mhz speeds etc.
• Tried all of the above using different connections i.e. DVI and HDMI.
• Flashed the bios to F15 and retried all of the above.
• Had the 7870 replaced in case it was faulty, and retried all of the above on the F15 bios.
• Checked the voltages on the PCIE power connectors, all fine, though only tested with a basic multimeter.

Any thoughts?
I'm thinking PSU or the MB is actually faulty, have had to reset MB BIOS a couple of times though so I'm not ruling out the possibility that I have done something stupid in the BIOS (used optimised defaults to tests in a consistent manner though).
I didn't notice anyone else on the forum having the exact same problem, though I did notice this recent post which could be similar:
http://forum.giga-byte.co.uk/index.php/topic,9653.0.html

System Specs:
Intel Quad Core i7-3770K 3.50 GHz 8MB Cache LGA1155
Gigabyte GA-Z77X-D3H (Rev 1.0) Intel Z77 Chipset MB
Asetek 510LC Liquid Cooling system w/ 120mm Radiator
Kingston Hyper-X 8GB (2x4GB) PC12800 DDR3/1600mhz Dual Channel Memory
Gigabyte HD 7870 2GB GDDR5 16X PCIe 3.0 Graphics Card
Seagate 2TB SATA-III 6.0Gb/s 64M Cache 7200RPM Hard Drive
Corsair 650 Watts CMPSU-650TXV2 Gaming Power Supply

Cheers!

EDIT 1:
This seems similar to my problem too:
http://forum.giga-byte.co.uk/index.php/topic,9699.0.html

[KRIZ]

Sounds similar,its definately a recognition problem between the mb and card as I get no native vga output thru the 7870 either, but it works fine with 2 other cards  i have tried. Ill post the fix here .....if anyone decides to find one before i return the giga gear and try another brand after 5 yrs of flawless use.

[o0Raven0o]

Thanks Kriz, I think I'm going to have to turn mine in too at this rate. Luckily my supplier has been following my problems and has been accommodating so far. Shall give it another 24 hours and see what feedback I get from Gigabyte, otherwise it's going to have to go 

[o0Raven0o]

Turns out that my problem was a SECOND, brand new, factory sealed 7870 that was faulty. Doesn't inspire me with confidence in the product! I am still yet to receive my rig back from the supplier to confirm for certain that everything is indeed working but, I have no reason to doubt their word at this time.

I am still yet to even receive a reply from my support ticket placed with Gigabyte. Poor show from them.

Thanks to everyone in the forum who offered help and advice. I shall post any further developments here should they arise.