The Power Supply Unit (PSU) is a critical component that converts AC (Alternating Current) from the wall into DC (Direct Current) used by the internal components of a computer. It ensures stable, reliable power delivery to the motherboard, CPU, GPU, drives, and peripherals.
| Parameter | Description |
|---|---|
| Wattage (W) | Total power output (e.g., 450W, 650W, 750W); must match system requirements |
| Form Factor | Most common is ATX; others include SFX, TFX for compact systems |
| Efficiency Rating | Indicates how efficiently it converts AC to DC (e.g., 80 PLUS Bronze, Gold) |
| Rails | +12V rail powers CPU, GPU; +5V and +3.3V for peripherals and logic circuits |
| Modularity | Cable design: Non-modular, Semi-modular, or Fully modular |
| Cooling | Typically has a 120mm/140mm fan; some high-end models are fanless (passive) |
| Connectors | ATX 24-pin, EPS 8-pin (CPU), PCIe 6/8-pin (GPU), SATA, Molex, etc. |
| Rating | Minimum Efficiency (at 20% / 50% / 100% Load) |
|---|---|
| 80 PLUS | 80% / 80% / 80% |
| Bronze | 82% / 85% / 82% |
| Silver | 85% / 88% / 85% |
| Gold | 87% / 90% / 87% |
| Platinum | 90% / 92% / 89% |
| Titanium | 90% / 94% / 90% |
Higher ratings = less heat, lower electricity bills, better component safety.
| Connector | Purpose |
|---|---|
| 24-pin ATX | Main motherboard power |
| 8-pin EPS (CPU) | Supplies power to the processor |
| 6/8-pin PCIe | Powers graphics cards |
| SATA Power | For SSDs, HDDs, optical drives |
| Molex | Legacy devices, fans, peripherals |
| Floppy Power | Very rare, for old floppy drives |
🔋 The PSU is often underestimated but plays a vital role in system stability, safety, and longevity. A quality PSU is an investment in your system’s future.