Hi Folks, thanks for maintaining a great site with a wealth of knowledge. I'm still a bit confused after searching around for answers, so I thought I'd post a question here.

I planning to build a RX580 gpu rig, starting out with 6 gpu cards and 1x/16x powered riser boards. The RX580 has 8pin pcie power slot and is rated at 185W by manufacturer. I'm using a modular Corsair 1200W PSU with six 8-pin PCIE sockets and six 6-pin "peripheral & sata" sockets.

1. I ordered risers with 6-pin power connectors. They come with SATA-6pin adapter cable, but as far as I read I should not use those? Is it safer to use a PCIE power splitter cable, and connect the card/riser pair to the same pcie socket on PSU?

2. The cards are rated at 185W but 8-pin PCIE cable delivers 150W, is it safe to split the cable for both the card and riser? Is the riser supposed to deliver an additional 75W thru the PCIE slot on top of the 8-pin power source? In that case, shouldnt I power the riser from a different PSU socket because 8-pin PCIE is rated for 150W ?

Also, any other suggestions/tips on how to split the power among two PSU would be appreciated. Thanks in advance.