Brand new rig as of last march, been debugging off and on since then. The main (and I hope last) issue, which is also the killer, is that one night my pc powered off and I couldnt get the pc to boot back up. The mobo is an Asus p9x79 deluxe and suddently when I turn on power, the vga light is on solid with the Q code b2. This code means legacy option ROM initialization according to the manual. I put in a gts 250 and it boots up fine, so I rma the 7970. I get it back a month later, put it in and wa-la, it works. For 2 days that is and then the same thing happened again. Put gts 250 in and call Asus. They convince me its the mobo and I put it in today. Same thing. At this point, Ive pretty much ruled out the RAM and the Mobo but I could use some input. I dont have another rig right now to test the 7970 but I may be able to soon if i can get it to a friends house. I spent so much money on this thing and its killin me!!! Any help would be awesome! So far, i get little in the way of searching this issue on the web. I spent a few hours with an Asus rep on the phone today scouring all of the bios settings/options until we exhausted all his ideas. This same thing happens with the 7970 in ALL PCIE lanes. Only thing i havent tried replacing yet is the PS, which is a cooler master 850W silent Pro hybrid. I changed out the two 6+2 pin cords to the gpu.
7970 worked for 2 months,then quit.
7970 worked for 2 days then quit.
PC boots with gts 250
If both GPUs are installed, no boot.
New mobo, same problem
It sounds like the PS could be the culprit, if you have a local computer shop in your area I would pop in and get a couple molex to 6-pin connectors and go back to your buddy's and try to run the card. Just make sure to run the adapter on separate rails.
Also check your BIOS and make sure that the PCIe lanes are running at the right bandwidth ie PCIe 2.0 or 3.0. I only say that because your error states "legacy option ROM initialization"
The chances of two 7970 crapping out are almost impossible. Your gts 250 worked fine its not pushing your PSU at all. The 7970 requires strong amperage on the 12v rail, so there is a very strong possibility that you have a defective psu.
Ok, so local pc shop is pretty much a no go. Every place wants damn near 100 bucks just to see if my gpu works in their rig!!! I found a guide to test my psu with a digital multimeter while running prime95. I did this and the voltages were all seemingly good. Did this rule out the possibility of a psu defect? Not even sure i ran prime95 in the right mode, but I think I did.
How could you allow that Garbage to feed your Radeon HD 7970 I kid I kid
No but seriously I'd stick with OCZ, Antec, XFX, Corsair, NZXT, Silverstone, Seasonic, PC Power & Cooling and the High End Thermaltake PSUs. Those rated 80 Plus Gold at least if you're going to buy such a High End Graphics card. Those PSUs are made by reputable OEMs. JohnyGuru is a great place to get in-depth reviews but so is Toms.
Trust me you won't regret getting a good and solid power supply. It will reward you for the few extra bucks you spend with long lasting service, stable power delivery and a lower electricity bill at the end of the month.