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Chassis and CPU fans use either 3-pin or 4-pin power connectors. The 3-pin connectors are usually used for the smaller chassis fans with lower power consumption. The 4-pin connectors are usually used by CPU fans with higher power consumption.
Fans and onboard fan headers are backwards compatible. Proper fan connector placement is shown in the figures below.
Fan has a 3-pin power connector; desktop board has a 4-pin fan header
| Note |
When using a 3-pin power connector with a 4-pin fan header, the fan is always on; there is no fan control. | |
Fan has a 4-pin power connector; desktop board has a 3-pin fan header
Fan header pinouts
| Pin |
4-Wire Support |
Pin |
3-Wire Support |
| 1 |
Ground |
3 |
Ground |
| 2 |
+12 V |
2 |
FAN_POWER |
| 3 |
FAN_TACH |
1 |
FAN_TACH |
| 4 |
FAN_CONTROL |
N/A |
N/A | |
This applies to:
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