Chassis and CPU fans may use either 3-pin or 4-pin power connectors. 3-pin connectors are usually used for the smaller chassis fans with lower power consumption. 4-pin connectors are usually used by CPU fans with higher power consumption. Fans and on-board 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 will always be on; there is no fan control.
Fan has a 4-pin power connector; desktop board has a 3-pin fan header:
Something left uncovered? You are welcome to add information, explanations and fix errors, simply by clicking the edit link that appears on top of this page. There is no need to worry about accidentally damaging AllPinouts when adding or improving information, as other editors are always around to advise or correct obvious errors, and AllPinouts's software, known as MediaWiki, is carefully designed to allow easy reversal of editorial mistakes.