A power supply uses several distinct cable types, each serving a specific component: the large 24-pin connector powers the motherboard, the 4+4 pin EPS cable powers the CPU, PCIe cables power the graphics card, and SATA power cables run drives and other peripherals. Most PSUs, whether modular or not, come with all of these included.
- The 24-pin connector is the main cable powering the motherboard.
- EPS (4+4 pin) powers the CPU; PCIe cables power the GPU.
- SATA power cables run drives; Molex is an older, less common connector.
- Most PSUs come with all necessary cables included in the box.
24-Pin ATX Connector
The largest cable, with 24 pins in a single connector, plugs into the motherboard and delivers the primary power feed for the whole system. It’s keyed to only fit one way, following the general installation approach in how to install a motherboard.
EPS / CPU Power (4+4 or 8-Pin)
A separate cable, often shown as two 4-pin blocks that combine into an 8-pin connector, plugs into the motherboard near the CPU socket to power the processor specifically. Some higher-end motherboards require two of these connectors for additional power delivery headroom, detailed further in what is a VRM.
PCIe Power (6-Pin, 8-Pin, and 12VHPWR)
Graphics cards draw additional power beyond what the PCIe slot itself provides, requiring 6-pin, 8-pin, or the newer 12VHPWR connector, depending on the GPU’s power requirements. Higher-end cards often need two or more of these connectors simultaneously.
SATA Power
A flat connector with multiple pins in a row, SATA power cables run SATA SSDs, hard drives, and some case fan controllers or RGB hubs. Most PSUs include several SATA power connectors on a single daisy-chained cable.
Molex (4-Pin Peripheral)
An older connector style, Molex is less common on modern components but still appears on some case fan controllers, older drives, and certain accessories. Most current PSUs include at least one Molex cable for backward compatibility.
Which Cables Do You Actually Need?
For a typical build, you’ll need the 24-pin, one EPS cable (or two for high-end boards), one or more PCIe cables matching your GPU’s connectors, and SATA power cables for each SATA drive. If your PSU is modular, following what is a modular power supply, only install the cables your specific build requires.
Important: never use a Molex-to-PCIe or Molex-to-SATA adapter as a permanent solution for a modern GPU, since these adapters can’t reliably deliver the sustained current a graphics card needs, according to safety guidance from Tom’s Hardware.
Do PSUs Come With All These Cables?
Yes, essentially all power supplies, modular or not, include the full set of cables needed for a typical build in the box. If a specific cable seems missing, check your PSU’s included accessory bag before assuming it’s absent, since some cables ship bundled together or in a separate small pouch.
See also part diagrams from TechPowerUp and community photos on r/buildapc showing each connector type in practice.
Frequently Asked Questions
What does the 24-pin PSU cable connect to?
It connects to the motherboard, delivering the primary power feed for the whole system.
Do I need two CPU power cables?
Some higher-end motherboards require two EPS connectors for extra power delivery headroom; check your specific board’s manual.
Can I use a Molex adapter to power my GPU?
This isn’t recommended as a permanent solution, since Molex adapters can’t reliably sustain the current a modern GPU needs.
Do all power supplies include SATA power cables?
Yes, virtually all PSUs include SATA power connectors, typically several on a single daisy-chained cable.
