I connected my first pci-e riser to a rig and when I switch on the computer I get a message saying "Please install your PSU's 4 pin cable to the motherboards 4 pin connectors" (for extra power to the PCIE lanes). Do I have to do this? It is a powered riser with a gpu in it connected to a PCI-e x1 and there is one other GPU connected in the PCIx16 slot for a total of 2 GPUs.
The motherboard manual says when more than 3 GPUs are connected (i.e. 4 or more), then you must use this.