Asus V2-PE3 - Manual (Page 34)

2-18 Chapter 2: Basic installation
If your Serial ATA HDD has both 4-pin and 15-pin connectors at the
back, use either the 15-pin SATA power adapter plug OR the legacy
4-pin power connector. DO NOT use both to prevent damage to
components and to keep the system from becoming unstable.
5. Connect one end of the Serial ATA cable to the SATA connector at
the back of the drive, then connect the other end to a Serial ATA
connector on the motherboard.
6. Connect a 15-pin Serial ATA power plug from the power supply unit to
the 15-pin power connector at the back of the drive.
- OR -
Connect a 4-pin (female) power plug from the power supply unit to
the 4-pin (male) power connector at the back of the drive.
Serial ATA cable
Serial ATA power
cable