ATX specification voltages
From TPU Reference
ATX standard used in power supply units defines ranges for few different voltage rails. These rails are +3.3V, +5V, +12V, +5VSB (Stand By), -5V and -12V. Following table provides the ranges:
| Voltage rail | Tolerance | Minimum | Maximum |
|---|---|---|---|
| +3.3VDC | +/- 5% | 3.14V | 3.47V |
| +5VDC | +/- 5% | 4.75V | 5.25V |
| +12VDC | +/- 5% | 11.40V | 12.60V |
| +5VSB (Stand By) | +/- 5% | 4.75V | 5.25V |
| -5VDC | +/- 10% | -4.50V | -5.50V |
| -12VDC | +/- 10% | -10.80V | -13.20V |
Note that ATX PSU specifications v2.xx do not specify -5VDC rail anymore. In addition, +12V2DC is added, which has same voltage specs as +12VDC.
However, PSU that outputs voltages on the edges of the ranges, cannot be considered "good". Above numbers just specifies the standard.
