When comparing an ATX 20-pin power cable to an ATX 24-pin power cable, which of the following voltage values is found on the four extra pins?

+3.3v, +5v, and two grounds omits the +12v rail, which is one of the voltages present on the additional four pins.

The four extra pins on the ATX 24-pin connector carry +3.3v, +5v, +12v, and ground, extending the original 20-pin standard to meet the increased power demands of PCI Express slots and other modern motherboard components.

The -5v rail was deprecated and removed from the ATX specification before the 24-pin connector was standardized, so it does not appear on any of the extra pins.

The -5v rail does not exist on modern ATX 24-pin connectors as it was eliminated from the ATX12V specification, making this combination invalid.