[SOLVED] Graphics card is not recognized by the system (5600XT)

[Alex3]

I want to connect a new graphics card to my PC (Win7), but it is not recognized at all, as it is not there.

MB is Biostar tb85, Intel i5 4 gen CPU, GPU is ASUS 5600XT T6G, and I try to connect it through PCI-X (1x) TO PCI-X (16X) Riser card because the GPU does not fit in my ATX case.
The MB onboard graphics unit works fine.
The riser is good because I connected an ancient NIDIA GeForce 210 through it, and it worked fine on multiple PCI slots.
Now, when I connect the 5600 it powers up, the LED lights up but the fans never start, ever. If it is connected only on the PSU (600w) the LED does not light up, when it is connected to both PSU and MB the LED lights up.
I updated the BIOS and tried tweaking it but I never got it right. I suppose that the problem is in the BIOS setup.
On couple of times it showed that there is an USB device that is not recognized, but I can not install drivers for the GPU because the AMD driver utility does not see a GPU on the system.
The 5600 is a PCI gen 4.0 and the MB has PCI gen 3.0 and 2.0 connectors.
I supposed that I would find a solution but for 3 days messing around my PC I came up with nothing.
I connected the GPU to an old AMD Athlon 4600 with MSI motherboard and it was the same, just LED on, no fans spinning.

What do you propose I should do?
I can take the 5600 to a friend who has a gaming PC so I can try if I got a faulty one.
Maybe the different PCI gen is a problem.
Maybe the Win7 is a problem (it is a legacy BIOS not UEFI) and on Win10 will work fine.

 

[rgd1101]

try a x16 riser card?

 

[ZeroDollarBudget]

You'll have to start by using DDU - Display Driver Uninstaller to clean all previous graphics drivers, then hook up the 5600 and see if it boots... if it does install the drivers and DONE!

Start by doing the driver clean and then check to see if it works, then move on to trying different PCI slots. and try it in your buddies system too for good measures.

Worst case, try a bios reset by removing CMOS and unplug the psu for 10-ish minutes then re-boot!

 

[Alex3]

We found a solution, a simple one. The card has both 8pin and 6pin power connectors. I never plug them both in. We connected both, rebooted, and the card got instantly recognized. We installed the drivers and everything is OK now.