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Question Is it safe to use molex connect to psu then to a hub that connects to cpu fan? The hub has 5 splitter for pwm fans connection.

Jun 14, 2020
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Is is safe to use the hub ? Im using a320m pro v2 m2. It has one cpu fan. One jled1. So im planning to buy 3 pwm case fan. Is this the best and safe way to power the fan ? Is there any options much more safer for my pc health ?
 
Do NOT use a fan splitter for the CPU fan header. ONLY the CPU fan or specific aspects of pumps (and such) should be hooked there.
Typically a molex fan hub is only going to power the fans (CASE fans) at full speed.
You can get headers that power from molex and use the motherboard CASE fan header to make variable speed.
You can get headers or splitters that power from the CASE fan header to a couple of (generally a max of 3) fans.
 
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kanewolf

Titan
Moderator
Is is safe to use the hub ? Im using a320m pro v2 m2. It has one cpu fan. One jled1. So im planning to buy 3 pwm case fan. Is this the best and safe way to power the fan ? Is there any options much more safer for my pc health ?
Motherboards want to monitor the RPMs of the CPU fan to protect the chip. Powering the CPU fan from a fan controller powered by a molex plug prevents that monitoring. I don't recommend it, and your motherboard may not boot without a CPU fan RPM reading.
 
Reactions: azammarodz
Jun 14, 2020
3
0
10
0
Do NOT use a fan splitter for the CPU fan header. ONLY the CPU fan or specific aspects of pumps (and such) should be hooked there.
Typically a molex fan hub is only going to power the fans (CASE fans) at full speed.
You can get headers that power from molex and use the motherboard CASE fan header to make variable speed.
You can get headers or splitters that power from the CASE fan header to a couple of (generally a max of 3) fans.
Thankyouu so much for the help.
However i got some confusions here.
Is it safe to connect like that ? From psu to molex and then to case fan header(sys fan) which power the hub ? Or can I just use the power supply to power the molex then connect the pwm case fans to it ( run full speed ). Btw sys fan header can monitor speed and control ? Or maybe should i use splitter to power 2 fans then use hub to power others fan. Btw is pwm header same with case fan/sys fan header ?
 
Jun 14, 2020
3
0
10
0
Motherboards want to monitor the RPMs of the CPU fan to protect the chip. Powering the CPU fan from a fan controller powered by a molex plug prevents that monitoring. I don't recommend it, and your motherboard may not boot without a CPU fan RPM reading.
I see thankyou!, Do you think molex to pwm connector is okay to power pwm fans ?
 
Is it safe to connect like that ? From psu to molex and then to case fan header(sys fan) which power the hub ? Or can I just use the power supply to power the molex then connect the pwm case fans to it ( run full speed ). Btw sys fan header can monitor speed and control ? Or maybe should i use splitter to power 2 fans then use hub to power others fan. Btw is pwm header same with case fan/sys fan header ?
The fan header will have specific hookups for it based on what you buy, so pay attention to that aspect.
There are adapters where you can run from molex or sata to a fan plug and yes, it will just run full speed.
There are headers that power from molex or sata and use (for instance) the mobo fan header to monitor for fan speed. I would assume they still sell the type header with a knob to adjust fan speed.
This is all going to be very hardware specific.
 

Karadjgne

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Ambassador
With 3pin fans, the hub is a powered splitter, molex provides the power for the fans and thats it, any attachment to the motherboard just reports the speed.

With 4pin PWM fans, it too is a molex powered hub, except it's actually a double splitter. First is power is supplied to every fan, but the second is the pwm control applied simultaneously to all fans directly from the motherboard.

A 3pin powered hub has zero control, all power coming from the molex, and the pwm hub has full control of all fans as a single unit, as the signal comes from the motherboard independent of the power.

Don't mix 3pin and 4pin fans. Its not healthy for the fans unless planning on full time full speeds. The 12v motors in a pwm fan do not like being run at the 5-7v that 3pin fans are rated for at minimum.

So first figure out exactly what you have, what headers, what control, what fans, then figure out what you need to get them working within your expectations and desires.
 

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