Do you have a way to measure the power draw, either from a kill-a-watt meter or similar. I also think that 2 x 1000 Watt PSUs per rig should be more than enough power, how is the load spread between them, pretty much 50-50, or 5 card and 3 cards + system? How often have the reboots been? The more information you can provide the easier it will be for someone to help you.
You could maybe try to remove 1 card for a day just to see if that helps, as that would also point to power issues if the rigs run ok with a reduced load. Also, how are your risers powered? If you are using the SATA power adapter, those can cause trouble once the power draw gets too high. Best to use risers with 6-pin PCIe or 4-pin Molex connectors and feed no more than two risers per chain (cable).
The load is spread pretty evenly. 2 Risers per chain. Each card has its own line. I think it could be the fact that I never changed the voltages from old setup. I'll try them again tonight with stock voltage settings. There is enough power, but If I'm limiting it via my settings in Claymore, then it is the only thing that makes sense.
Also, for the previous reply - I'm using 8 x RX580's and using Claymore dual mining software. Mining Ether and Decred