3.3 V, 5 V
3.3 V, 12 V
5 V, 12 V
3.3 V, 5 V, 12 V
P2 connector for plugging in auxiliary components
P3 connector for plugging in case fans
P4 connector for plugging into Pentium 4 and later motherboards
Aux connector for plugging into a secondary power supply
Red = 3.3 V; Yellow = 5 V
Red = 5 V; Yellow = 12 V
Red = 12 V; Yellow = 5 V
Red = 5 V; Yellow = 3.3 V
To maintain good airflow inside your case.
It helps keep dust and smoke out of your case.
Both A and B are correct reasons.
Trick question! Leaving a slot uncovered doesn’t hurt anything.
Two primary voltage rails, 12 volts and 5 volts, and an auxiliary 3.3 volt connector.
Three primary voltage rails, one each for 12-volt, 5-volt, and 3.3-volt connectors.
One primary DC voltage rail for 12-volt, 5-volt, and 3.3-volt connectors.
One voltage rail with a 12-volt connector for the motherboard, a second voltage rail with a 12-volt connector for the CPU, and a third voltage rail for the 5-volt and 3.3-volt connectors.