Question: must connect power to psu?
Answer: 24-pin power to motherboard (always required)
4/8-pin EPS12V power to CPU (always required)
6/8-pin power to video card (normally required)
SATA power to storage devices (normally required)
MOLEX power to accessories (optional)
CPU fan & case fan power (required)
Power cable to system's power supply (always required)