Topic: cannot setup 2x7970, both cards can work solo, 0.2 btc bounty (Read 1260 times)

Sorry guys, nothing has worked. I suspect bad motherboard.

have you put a dummy plug into or connected a monitor cable to the second card? and is the one thats always detected the one being used for your display? if so then the second card may not be turning on. It's also possible that it migt be power related. i can definitely say not to use crossfire though, crossfire never scales 100%.

Are there any yellow icons in device manager?  I had a similar issue with trying to run 2x 4850s. Other card wasn't recognized. I went Into device manager and saw a generic display adapter with the yellow caution icon. I right clicked on it , removed it, and then went to "scan for hardware changes" . it refound the second card, but instead of showing the caution icon it automatically realized it was an amd card. It installed drivers,  I restarted and vamos. Everything worked corectly and it saw both cards.

I will try to use some of your advices today, I will let you know guys, thanks!

tried that, but nothing

What I meant is that if there is only one card then PCIe runs with 16x speed. And if there are two then the bandwidth is shared and this is what I see. GPU-z sees one card on PCIe 8x, so I guess, it switched into sharing bandwidth. But the second card cannot be seen - nowhere, not in dev man, now in the GPU-z. I run Gigabyte, they were good so far.

Take the bad card out, and clean the PCIe connectors with the eraser from a #2 pencil. Then go into the BIOS and disable everything you can that you don't need: audio, firewire, secondary SATA, LAN (?), etc. I don't think those UD3 boards allow you to adjust your PCIe latency, do they?

why not just crossfire them? It'll force the device manager to recognize?

Can you try a different motherboard? I know this seems unreasonable, but "disappeared gpu's from device manager" is usually something the motherboard or BIOS is causing. I've only used MSI boards so I haven't had an issue like this yet.

"I am putting them into the 16x and 8x slot, so both are running at 8x and it is detected by gpu-z" I am confused by this part. You say that it is not detected in Device manager but it IS detected in GPU-Z. This sounds fishy. Do you happen to have an "Unknown Device" in device manager when this happens? Are the sensors for the second, "detected but not detected" card all weird, like 0MHz core but 3174MHz memory, strange readings like that?

ok try this
take out the cpu, take a closer look on the cpu socket on the motherboard, see if there is no broken or twisted pin, if everything is fine, just clean the other side of the cpu, sometimes bad contacts can cause cpu lanes not communicating with the mobo which result to  pcie slots not working together or DDR3 memory malfunction  as symptoms

Correct.
Also, only one device is detected in device manager and the same is true for linux (checked with lspci).

I posted this, because I really need fresh ideas how to solve this problem. Unfortunately, I don't have more video cards to experiment with, just those two. Also, I don't have another motherboard which I could use for crossfire.

Hi,

So just to check, when you start cgminer, does it only come up with one device, i.e device zero?

Both have connectors plugged in. Only Sapphire shows up in Device manager when both are plugged in, though if only PCS is plugged in it shows up without problem. No option for Crossfire in CCC because only one card is detected.

One more thing to everyone. I will try out your suggestions after may 15th and will give out the bounty after that.
Thanks for reading!

Hi seems silly but are you sure both cards have their correct power cables plugged in? Do they both show up in device manager? Crossfire turned on in CCC?

Hi
I am banging my head against this problem for a while
I have Sapphire 7970 Ghz Edition Vapor-X
and Powercolor PCS+ Vortex II 7970
Each card mines fine on its own. However if I put two of them into my motherboard (GA990XA-UD3) only Sapphire is recognized.
Funny enough it does not matter which of the two PCIe slots it is in, always Sapphire is seen, not PCS+
Both cards spin fans. I tried a crossfire bridge, but no success. I am putting them into the 16x and 8x slot, so both are running at 8x and it is detected by gpu-z (this is how the mobo works - it is 16x for one card, 2x 8x for two).
I have also tried 1x to 16x riser for one of the card with second in the 16x slot and again, does not matter where, Sapphire is recognized.
That is both Windows and Linux can only see this card and so is cgminer.
I flashed motherboard bios to latest version.
I have latest drivers on Linux and Win. Though I think the other card should at least be seen by the system.
I have only 650W power supply (which itself is a high efficiency one - can output up to 54A of 12V - up to 648W), but I lowered voltage on the CPU and I think when the cards are just booting, they should boot up fine and be recognized and only at full load there may be a problem with throttling.

Thanks!

Any help is appreciated and there is small bounty for successful advice. (I am thinking about 0.2 btc - I am a late btc adopter and I did not manage to become filthy rich yet

I thought I am knowledgable about computers, but this is getting ridiculous