Using 4 risers already powered I also have to use the two extra power connectors on the board (PCIE_PWR1 and PCI_PWR2) ?
If using all powered risers, there is no need to use the extra molex power connectors on the board. You do need to disable the power check in the Bios or it will give you an error message at Post.
Thank you !!!
Even if there will be no message it will have various(?) issues (frankly speaking since I built 4 of those this week I don't remember what it was exactly, but something you definitely want to avoid) and as you're most likely using multiple PSUs, just find one spare molex, attach to the board and make your life easier.
EDIT: lol... sorry I missed "4 raisers" the issues I'm talking about were apparent after 12 cards were added.