+5 VSB or “+5 V standby” supplies power even when the rest of the supply lines are off.This connection allows for remote sensing of the voltage drop in the power supply wiring. +3.3 V sense should be connected to the +3.3 V on the motherboard or its power connector.It remains low for a brief time (100–500 ms) after the PS_ON# signal is pulled low. PWR_OK or “Power Good” is an output from the power supply that indicates that its output has stabilized and is ready for use. The CORSAIR 12 pin GPU Power Adapter Cable connects any Type 3 or Type 4 CORSAIR modular power supply directly to any GPU using the 12 pin GPU power. I have a spare PCI-E power slot on my power supply that i was going to buy an 8 pin connector cable.To check your stand alone ATX power supply, simply connect the PS_ON# wire (green wire) to the grounding wire (black). It is internally pulled up to +5 V inside the power supply. To maintain compatibility with existing systems and power supplies, Nvidia and its partners will bundle a special 3x8-pin to 12VHPWR adapter with every GeForce RTX 3090 Ti graphics card. When the line is connected to GND (by the motherboard), the power supply will turned on. If at all possible, use three separate 8-pin connectors. PS_ON# or “Power On” is a signal from the motherboard to the power supply.There are 4 wires which have special functions: In modern desktop computer system, there are two connectors for the motherboard: a 4-pin auxiliary connector providing additional power to the CPU, and a main 24-pin power supply connector, an extension of the original 20-pin version.

An ATX power supply has several peripheral power connectors.

Originally the motherboard was powered by one 20-pin connector.

Power supply with 3 8 pin connector