Re: GPU 1 on Gigabyte Motherboard is always generating HW errors
Wow, you probably hit on of the eletronic / tech issues where there's no explanation 
You did a good job already trying most common problems, bios update, change risers, GPUs etc
You can try to change some settings on bios for sure
I have another motherboard, but I had some issues with 3 cards, the motherboard only recognized 2, no matter which positions, so I change settings on Bios, specifically on PCI-e section, and after some try and errors I found the issue.
You can try to change 1 parameter at time and see how it goes
Another thing to try, put a monitor or a adaptor on this GPU1
Try to clean this slot with isopropyl alcohol or a clean contact product
After that, I don't have more ideas, let's see if some person here have some idea
Or, you slot could be broken, some contact or pci lane is damaged
You did a good job already trying most common problems, bios update, change risers, GPUs etc
You can try to change some settings on bios for sure
I have another motherboard, but I had some issues with 3 cards, the motherboard only recognized 2, no matter which positions, so I change settings on Bios, specifically on PCI-e section, and after some try and errors I found the issue.
You can try to change 1 parameter at time and see how it goes
Another thing to try, put a monitor or a adaptor on this GPU1
Try to clean this slot with isopropyl alcohol or a clean contact product
After that, I don't have more ideas, let's see if some person here have some idea
Or, you slot could be broken, some contact or pci lane is damaged
Thank you for your reply
I tried mostly everything in the bios, on pcie and other parameters... nothing changed.
I cleaned the slot, but the problem is still there.
I don't think it's the slot itself. Like I showed on this picture :
https://ibb.co/7S7qNX1
I removed the riser from slot PCIEX1_1. I moved this card with the riser to slot PCIEX1_5.
On PCIEX1_5 there was no HW errors.
The card that was on PCIEX1_2 was running fine too before I moved the PCIEX1_1 to PCIEX1_5.
But after moving the PCIEX1_1 card, the PCIEX1_2 card was generating a lot of HW errors.
On the mining software, the PCIEX1_2 card was displayed as GPU1.
Very strange thing..