I'm wondering if anyone has had a similar issue to the following.
A few months back now I built a whole new PC, since day 1 I have been having some issues. i7 3820, Gigabyte GTX670, Gigabyte X79-UD3 MB, 850Watt Corsair PSU.
Whenever I turn my PC on usually about 2 of every 3 times the PC does not post and I get the error code of 1 long beep 2/3 short beeps which I found out means an issue with the video card or monitor not initiating correctly. But on that other time it posts, loads windows and works perfectly, the card doesn't miss a beat even when playing games on ultra.
Since then I have tried a friends graphics card in my PC and I do not get this issue, PC posts 100% of the time, which would lead me to think the rest of my setup is fine and it is the graphics card at fault, however when I put my 670 into another PC, I never get this issue, always posts, always works fine.
So from this I gather it shouldn't be the graphics card, shouldn't be my motherboard, I have swapped the RAM around and doesn't seem to make a difference, I have updated the MB Bios...
To me it seems like the Motherboard and Graphics card do not get along at all, but change them to any other system and they work 100%. I feel as though I have covered all of the main bases but if there is anything else you can suggest that would be greatly appreciated since I cant really send any parts back knowing that they work fine independently. Is it possible there is just some incompatibility between my MB and graphics card (Driver, Bios, the motherboard said something nasty about the graphics cards mother?)
Do you have IGPU activated in bios? Are you using Virtu MVP? I was having a similar issue when my integrated graphics card was activated and using lucidlogix virtu mvp. I uninstalled the intel graphics driver and disabled integrated graphics and the problem stopped. Also, you might want to make sure your graphics card's bios is updated as I was having other issues prior to updating that. You could try using the Gigabyte VGA Bios tool to upgrade to the latest.