15 & 16 and 16 & 17
If it as a 20 or 24 pin connector and a 4 pin connector then it is a ATX power supply.
There should be a large connector coming from the Power Supply unit. You may have a 20 pin or a 24 pin connector on your motherboard. Most power supplies come with a 20+4 pin connector which allows them to connect to both 20 and 24 pin mother bards.
24 pin connector is required to supply power to the motherboard.
power supply
The atx 12 connector is one of the motherboard power connectors and used for 12 volt power connect for cpu voltage regulator.
Many/most motherboards have a separate power connector for the CPU. Check your motherboard's installation instructions to locate the CPU power connector. Then connect the matching power supply cable to the CPU power connector on the motherboard.
The most common power supply connectors for motherboards will be either a 20 or 24 pin connector. Older unit used less pins like the ATX but the cure standard is the 20 or 24 pin main connector.
The SATA connector on a power supply is to supply power to SATA-based hard drives. It is not to be confused with the ATX plug that is to give extra power to the CPU, nor the PCI-e power connectors that give extra power to certain video cards. It is unexpected to find a SATA style connector on the motherboard.
24-Pin
a cable from the power supply to the Berg power connector on the FDD a cable from the 20-pin ATX power connector socket on the motherboard to the Berg power connector on the FDD
If you are refering to the 20 or 24 pin molex connector, this is the motherboard power distribution subsystem from the power supply. If you are refering to the several other small connectors, they have various functions. Front panel indicators and switchs, USB distribution connectors, fans, CD audio, etc.
A SATA power connector is what connects the SATA device to the PSU (power supply unit), therefore giving it a source of power. There is another cable that connects to the motherboard but that is just for data transfer.