8 pin MOLEX 39-01-2080 connector at the cable.
2x4 pin connector at the cable.
Many power supplies come with a 4+4 pin 12 volt cable which is compatible with both 4 and 8 pin motherboards.
The EPS12V (Extended Power Supply) 8-pin connector, also labelled EATX12V on motherboards, was defined by the SSI Forum (Server System Infrastructure) to deliver dedicated +12 V power to the CPU voltage regulator module on server and high-end workstation boards. It uses the same Molex Mini-Fit Jr. 4.20 mm pitch dual-row housing family as the ATX12V 4-pin CPU connector, with each contact rated at 7 A. A power supply may supply a single +12 V rail across all eight pins, or split them between two rails (12V1 on pins 5–6 and 12V2 on pins 7–8) to meet server platform requirements. Many consumer power supplies ship a 4+4 split cable that is electrically and mechanically compatible with both the 4-pin ATX12V socket and the full 8-pin EPS12V/EATX12V socket.
| Pin | Name | Color | Description |
|---|---|---|---|
| 1 | GND | black | Ground |
| 2 | GND | black | Ground |
| 3 | GND | black | Ground |
| 4 | GND | black | Ground |
| 5 | 12V1 | yellow | +12 V |
| 6 | 12V1 | yellow | +12 V |
| 7 | 12V1 or 12V2 | yellow | +12 V |
| 8 | 12V1 or 12V2 | yellow | +12 V |
Signals
- GND — Ground return for the +12 V supply; four pins (1–4) share the current load, each rated 7 A maximum.
- 12V1 — Primary +12 V rail feeding the CPU VRM; carried on pins 5 and 6, and on pins 7–8 in single-rail PSU implementations.
- 12V2 — Secondary +12 V rail present in dual-rail server PSUs; occupies pins 7 and 8, split from 12V1 for independent over-current protection.
Notes
The EPS12V 8-pin and the ATX12V 4-pin use the same Molex Mini-Fit Jr. housing family (4.20 mm pitch, series 5556/5569); because the 4+4 split cable mates physically with either socket, care must be taken not to force a 4-pin ATX12V half-connector into a keyed 8-pin socket incorrectly. The housing polarisation tab prevents reversal within the correct socket but does not prevent mechanical forcing of an incompatible connector. With four +12 V pins in parallel at 7 A each, the connector can deliver up to 28 A (336 W) in principle; platform thermal limits and cable ratings govern the practical ceiling.
Connector part numbers
- Motherboard connector: Molex 39-28-1083
- Cable connector: Molex 39-01-2080
- Terminals: Molex 39-00-0168, Molex 44476-1111
- Maximum current per circuit: 7 amps