that's fine per Rig 6 GPU i will do that
but do i need to buy new PSU or buy new PC mobo + ram + PSU?
Total 12 GPU
first rig 6 GPU
second Rig 6 GPU
Or buy new PSU for my Motherboard ?
Personally, I'm not a fan of mining rigs with more than 6 GPUs using risers, but since you are staring, you could just use the motherboard you have with one more PSU until you learn all you want to learn and decide what to do going forward