Anyone know why some power suppy units that use SATA as the connection type have sometimes 2-4 connectors?
Because they use both 12 volt DC and 5 volt DC, one set of wires is the negative and positive for the 12 volt, and the other set is the positive and negative for the 5 volt. Different devices use different voltages, and having both run in the same connector allows that to happen. That is why fans generally have two wires on the connector, because they use one or the other voltage. (yes I know fans connecting to the motherboard have 3 wires, but were not talking about those types)
so you can add more sata drives sata cdroms also require a sata power connector
