3 pin to 4 pin Adapter

I have some AF120 case fans. They have 3 pin connectors. All of the fan connectors on my motherboard are 4 pin. Please recommend a good 3 pin to 4 pin adapter.

 

Thanks!

You don't need one. Any recent motherboard has headers that both 3 and 4 pin compatible. Line the little bump up and slide them on. More significant is why the fan has a 3 pin or 4 pin female connection and it relates to motor type. 3 pin are DC motors and speed is controlled by altering voltage between 5-12v. 4 pin are PWM and change speed with a control signal while maintaining a constant 12v. You may need to set this in the BIOS under the fan control section.

Thanks for the reply. I already have my case fans but for future reference, is one fan type better than the other (DC vs. PWM)?

People sometimes have strong opinions on this topic, but it is mostly based on preference or familiarity than actual performance differences. The same blade moves the same amount of air in the same environment at the same speed. A DC or PWM motor won't change that. However, there are a few things a normal user may want to consider.

 

Minimum speed. Typically a DC fan has a 60% minimum run speed. PWM is usually less, sometimes as low as 20-25%. On a 1000 rpm fan, this likely makes little difference. In high speed fans with max speeds above 1500, this can be far more meaningful. A 1200 minimum on a 2000 rpm 140mm fan would be a lot to endure at the desktop. On high speed fans, you probably want PWM control.

 

A less common issue for some PWM fans is they may not react in the linear path expected on certain fan controllers. Once you figure out the behavior, it is easy to adjust your fan curve for the desired effect. DC voltage controlled fans are normally very linear in their response and you can roughly guess and be right. Just to make it more confusing, some PWM fans can be run in DC mode and work just fine. You can sometimes see this in the operational voltage range in the specifications.

 

The most important thing to consider is your control source. Most motherboard headers are dual, but this is not guaranteed. Some less expensive boards may still use PWM on CPU fan and standard 3 pin on other headers in cost saving measure. Also, when using the fans with AIO coolers, nearly all units that control fan speed from the device itself will need a PWM fan. Most fan models are one or the other, but there are a few that are identical other than a DC or PWM motor (and likely some deliberate range differences). The Corsair SP series is one of those, but there aren't many so the choice is made for you.