Fan headers

EdgarsXD · May 22, 2021

Is it ok if i plug my case fans into cpu_fan headers on my motherboard?

YoungBlade · May 22, 2021

As long as the fans are compatible with the headers, they'll work fine. The concerns would be:

1. The CPU fan headers are checked when the computer starts up to make sure the CPU has a fan for cooling, so if a case fan is plugged in instead, that check is now meaningless. Also, any monitoring software you use will show the status of the case fan as if it was a CPU fan. So when you're troubleshooting, you'll need to remember that.

2. If the fans are variable speed (4-pin, PWM) then their speed will be controlled by the computer as if they were used for a CPU cooler. Of course, if your CPU is heating up, having the case fans ramp up is a good thing. This would really only be a problem if the fans are set to vary speed based on CPU temp and you happened to be in a situation where the CPU was cool, so the fans turned down, but then the GPU started to heat up because of the reduced airflow in the case. This can happen with games that aren't very CPU intensive, and also when doing GPU-only tasks like GPU renders, F@H, mining, etc.

EdgarsXD · May 23, 2021

19 hours ago, YoungBlade said:

As long as the fans are compatible with the headers, they'll work fine. The concerns would be:

1. The CPU fan headers are checked when the computer starts up to make sure the CPU has a fan for cooling, so if a case fan is plugged in instead, that check is now meaningless. Also, any monitoring software you use will show the status of the case fan as if it was a CPU fan. So when you're troubleshooting, you'll need to remember that.

2. If the fans are variable speed (4-pin, PWM) then their speed will be controlled by the computer as if they were used for a CPU cooler. Of course, if your CPU is heating up, having the case fans ramp up is a good thing. This would really only be a problem if the fans are set to vary speed based on CPU temp and you happened to be in a situation where the CPU was cool, so the fans turned down, but then the GPU started to heat up because of the reduced airflow in the case. This can happen with games that aren't very CPU intensive, and also when doing GPU-only tasks like GPU renders, F@H, mining, etc.

but if they are not PWM (3 pin) fans then it's still fine?

YoungBlade · May 23, 2021

4 hours ago, EdgarsXD said:

but if they are not PWM (3 pin) fans then it's still fine?

Then the only issue is that your computer will think it has fans for the CPU that it doesn't have, but that's only an issue if your CPU cooler fails and the system doesn't bother to notify you, or if you need to troubleshoot and get confused about CPU fans because you forgot that the "CPU fan" it shows is actually a case fan.

The fans should work just fine.