Power Supply Standards
80 Plus efficiency tiers, ATX versions, and regulatory standards for PSUs.
Reference
80 PLUS efficiency (230 V, 50% load)
| Tier | 20% load | 50% load | 100% load |
|---|---|---|---|
| 80 Plus | 82% | 85% | 82% |
| Bronze | 85% | 88% | 85% |
| Silver | 87% | 90% | 87% |
| Gold | 90% | 92% | 89% |
| Platinum | 92% | 94% | 90% |
| Titanium | 94% (@10% load) | 96% | 94% |
ATX versions
| Version | Year | Notable changes |
|---|---|---|
| ATX 1.x | 1995 | Original 20-pin main connector |
| ATX 2.0 | 2003 | 24-pin main, PCIe rails |
| ATX 2.2 | 2005 | EPS 8-pin CPU |
| ATX 2.31 | 2008 | Tighter efficiency, standby 0.5 W |
| ATX 3.0 | 2022 | 12VHPWR PCIe 5.0 connector; power excursion 2× rated |
| ATX 3.1 / PCIe 5.1 | 2023 | 12V-2x6 replaces 12VHPWR (stronger contacts) |
Connectors
| Connector | Pins | Use |
|---|---|---|
| Main | 24-pin | Motherboard |
| EPS CPU | 8-pin | CPU power |
| PCIe (legacy) | 6 or 8-pin | Older GPU |
| 12VHPWR | 16-pin | RTX 40 / new GPUs (up to 600 W) |
| 12V-2x6 | 16-pin | Updated 12VHPWR — sturdier |
| SATA power | 15-pin | SATA drives |
| Molex (legacy) | 4-pin | Fans, older peripherals |
Regulatory
- EN 61000-3-2
- EU harmonic current limits
- Energy Star
- US efficiency program
- DoE Level VI
- External power supply efficiency (wall warts)
- ErP Lot 7
- EU external PSU ecodesign
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