Stuck ! Two different GPU AMD models, one not detected by the system

[headmaster200]

Hello,

I've been stuck with this issue for over a month now, and haven't been able to figure it out. Got no replies regarding this issue several days back so I'm trying again, I'm really clueless about how to solve this, so any help is greatly appreciated.

I have just finished building a rig but have stumbled on a problem regarding the GPU's.

I have two models of GPU's connected to a motherboard. 2 x 6970's and 1 x 7950.

The issue lies in that the 7950 is not detected in the system. All graphic cards are connected through risers as below.

16x to 16x riser --> 6970 GPU
16x to 16x riser --> 6970 GPU
16x to 1x riser --> 7950 GPU

I have stumbled upon a similar problem once and then it was to unplug all cards except the third ( not detectable ) and let it install the drivers, the issue now is when I unplug the others and plug in a screen I cannot get any video output at all from the card, thus I'm unable to install anything, something must be wrong?
Moreover, I can connect to the computer through TeamViewer, and there i can get a picture when only having the not detectable card plugged in, but the picture is all blurry and buggy so I can't make any sense of what I'm clicking and where the pointer is.
Note that the card is still connected through a 16x to 1x riser to the computer.

The 7950 card should work just fine but somehow I cannot install the drivers needed to make it show up, or maybe I must write in some code into console?

The motherboard is : Asus P5K Premium, if that makes any difference, and should be able to run 3 cards through risers ( note : the GPU's are not connected through bridge ).

Many thanks in advance!

 

[smeezekitty]

I cannot figure out why you would set it up like this. In any case, did you try the 7950 in a x16 slot?

 

[Avro Arrow]

I cannot figure out why you would set it up like this. In any case, did you try the 7950 in a x16 slot?

I agree with this. A PCI-Express x1 slot will not deliver enough power to even turn a Radeon HD 7950 on. You have more power from the twin HD 6970s in crossfire than from the lone HD 7950 so why are you even bothering with it?

 

[headmaster200]

I cannot figure out why you would set it up like this. In any case, did you try the 7950 in a x16 slot?

I agree with this. A PCI-Express x1 slot will not deliver enough power to even turn a Radeon HD 7950 on. You have more power from the twin HD 6970s in crossfire than from the lone HD 7950 so why are you even bothering with it?

Thank you both for your answers.

I've modified the computer to run for bitcoin mining and having risers is the most airflow efficient way.

Are you sure on this? I've seen people all the time running the applications I do through having 1x to 16x risers connected. The problem is really that I get no video output for some reason while the computer is clearly on and functioning otherwise.
The computer is able to boot up to the windows desktop and I can see (through TeamViewer) that there's a pop-up window regarding the driver installs, but when connecting a screen I get no video output and when trying to connect through TeamViewer which I've installed the image is all blurry and buggy, but you can still see that there's a pop-up there.

Have not yet tried to connect it to the 16x solely but guess I should try that.