Last updated February, 2018
It’s a common problem – a multiple GPU mining rig has one GPU that isn’t hashing as well as it’s brother and sister GPUs. The question is asked in a forum, or other message board, because the rig owner wants someone to fix it for them. But all too often, no details are given, and no troubleshooting has been done.
The first step, and the easiest, before you start rolling back Windows updates, or reinstalling drivers, or updating firmware, is to swap GPU positions. Power down your rig, and move the GPU that is hashing properly into the spot where the GPU isn’t hashing properly.
This can help determine if there is a hardware problem with your PCIe slot, your GPU riser, or riser cable.
After swapping positions, if the problem follows the problematic GPU, then the problem is with the GPU. That’s when you can start trying things like updating firmware, or looking at warranty options etc.
If the problem stays in the same slot and occurs with more than 1 GPU, then the problem is somewhere else.
Start swapping out riser cards, power cables, etc to that position to see if that changes anything.