To provide power to large internal Devices such as hard drive or CD/DVD drives and sometimes case fans or other devices.
Just adding this.
Powers IDE drives.
molex 4-pin
stop cheating!
Typically a 2, or 3 pin 'fan' connector, or a 4-pin 'molex' connector. The 2-pin (positive/negative) and 3-pin (positive/negative/RPM) are most common, but older or cheaper fans, especially those not used on the CPU heatsink, may use a 4-pin 'Molex' connector. Other connectors may be used, including proprietary connectors, in the case of some motherboards, CPUs, and cases. This is common in videocards, which may need 2/3 pin, 4-pin molex, 4-pin PCI-E, 6-pin PCI-E, or 8-pin PCI-E connectors, or a combination thereof!
Molex Connectors are used in Power Supplies for powering up the devices. There are different types of Molex Connectors on Power Supply for. eg. 20 or 24 Pin Power Connector\ 4 Pin IDE device \ Sata Device Connector.Mini Molex refers to connector powering Floppy Disk Drives or AGP Cards on Computer System.
There are two kinds in common use:Molex - an older standard, but still commonSATA - Serial ATA, a newer standardSee the related links for pictures.
All PATA (Parallel ATA) drives use the Molex 4-pin power connector. This connector provides the necessary power to the drive, supplying +5V and +12V to operate. The Molex connector is typically used for older hard drives and optical drives before the transition to more modern interfaces like SATA.
A Molex power connector is a 4-pin power connector found in most computer power supplies. It is used to provide power to large internal drives like hard drives and CD/DVD drives. They are slowly being replaced by SATA power connectors, which are easier to install can cannot be inserted incorrectly. They should not be confused with a Berg connector which is much smaller and is used to power floppy drives. The molex connector is used for IDE drives
provide more power for the CPU
The number and type of power connectors provided by a power supply can vary widely depending on the model. Common types include 4-pin Molex connectors, 6+2 pin PCIe connectors for graphics cards, SATA power connectors for drives, and 24-pin ATX connectors for the motherboard. For instance, a typical power supply might provide three 4-pin Molex connectors, four SATA connectors, and two 6+2 pin PCIe connectors. Always refer to the specifications of the specific power supply for accurate details.
Keep in mind I'm not a computer repair guy or at least not officially. The four pin molex connector from a power supply unit that you use to plug into hard drives, and other drives has a 5 volt wire and a 12 volt wire. The two black ones are ground or negative. The red wire is 5 volts DC, the yellow is 12 volts DC.
The system currently uses three types of power connectors: a 24-pin ATX connector for the motherboard, an 8-pin (or 4+4 pin) CPU power connector for the processor, and one or more 6-pin or 8-pin PCIe connectors for the graphics card. Additionally, there may be SATA power connectors for storage devices and 4-pin Molex connectors for other peripherals. The exact number and type can vary based on the specific hardware configuration.
the optical drive will connect to the power supply with a connector called molex connecter it is a 4 prong connector