[SOLVED] Safe to use a molex hub for case fans?

Solution
1) you are more likely to break the fan header on the motherboard by doing that, not the entire motherboard.

2) no, it is not possible. if it does happen, you have something very, very, very, very wrong with the power supply

rubix_1011

Contributing Writer
Moderator
So, your question is whether it is 'safe' to use a connector that comes shipped with a product?

Looks like molex power and 3-pin for voltage control, so ideally you would use one or the other with the motherboard being able to manage the speed via 3-pin or full speed with the molex.

Using both gets you full speed.
Using only molex gets you full speed.
Using 3-pin only gets you ability for speed control with motherboard.
 

Paperdoc

Polypheme
Ambassador
WAIT! Do NOT plug in BOTH the 3-pin connector and the Molex connector on any fan! Doing that will force power backwards into your mob fan headers. Do ONE of them only and leave the other connector unused.

Connecting a fan to a Molex power output from the PSU will have it run full speed all the time, and the mobo will not be able to show you its speed OR to detect fan failure (zero speed). Of you plug the 3-hole smaller fan connector into a mobo fan header instead AND configure the header to use the older Voltage Control Mode (aka DC Mode) - NOT the new PWM Mode - then the mobo will control the fan speeds, slowing them down when your workload is light and generating less heat. It also will monitor the fan speed reading to be sure it is still running.
 

bioax

Commendable
Nov 30, 2019
268
42
1,790
So, your question is whether it is 'safe' to use a connector that comes shipped with a product?

Looks like molex power and 3-pin for voltage control, so ideally you would use one or the other with the motherboard being able to manage the speed via 3-pin or full speed with the molex.

Using both gets you full speed.
Using only molex gets you full speed.
Using 3-pin only gets you ability for speed control with motherboard.
Yeah but I was wondering if it is possible for the PSU to possibly "fry" like how the motherboard would if I connected too many fans to one header.
 

rubix_1011

Contributing Writer
Moderator
1) you are more likely to break the fan header on the motherboard by doing that, not the entire motherboard.

2) no, it is not possible. if it does happen, you have something very, very, very, very wrong with the power supply
 
Solution