Are there motherboards that have several x16 slots on them? I belief more than one x16 slot will result in x8 mode? Correct me if I'm wrong here, I'm just trying to find a solution for zombie mode with 4gb rx570s
I think you're mixing 2 issues.
PCIe x1 is enough for mining, except for Nvidia LHR GPUs that include a lane test as one of their LHR triggers.
Zombie mode is a workaround for GPUs with only 4 GB of VRAM. It's a clever workaround, but only a workaround,
and it only allows mining at a significantly reduced hash rate. The solution is a GPU with more VRAM.
However, there is a connection between them. Zombie mode increases data exchange between the CPU and GPU
and requires more PCIe bandwidth. At some point it might bottleneck at x1 and reduce performance and may
work a little better at x2.