Only 8x Cards Work in PC

[DanielThePrawn]

So basically I have 2 Graphics Cards, a GTX 770 and a HD 7970, both 16x cards. However, none of these cards produce any image onto the screen when plugged into a PCIE 16X 2.0 Slot. However, when I plug in a GT 710, an 8x card, it produces an image on the screen and works perfectly.
I have tried 2 different 600W PSU's (A be quiet 600w Power 9 and an XFX PRO 650W) and still no difference. I have also tried two different motherboards (an Intel DQ67SW and an Intel DH61WW) and still no difference. All power connectors were connected properly and all connectors were pushed in.
I have gone into the BIOS and enabled video through PCIE and still no image. Any help is appreciated, thanks!

 

[andy_mk3]

two different motherboards (an Intel DQ67SW and an Intel DH61WW)

I would say these are likely your issue. They look like very generic boards, which often have a limited power output on the PCI-E header. I can only suggest a BIOS update if available may help but it's unlikely.

 

[DanielThePrawn]

Oh alright, so say I got an MSI one it may actually work since it would supply more power? Sorry, I'm not all too familiar with older boards.

 

[CuriousTomCat]

Update the motherboards bios

 

[pingu666]

ive had a damaged board, something in the slot not soldered right, or broken, ran at 8x but not 16x. you can maybe get a 8x to 16x riser and see if card work that way

 

[DanielThePrawn]

Well I've updated the motherboard bios and it still doesn't work. Putting the gpu in just causes the pc to restart constantly. I don't think it's a soldering problem as I've tried this on 2 motherboards and it doesnt work on each.