[SOLVED] Is it safe connecting 3 Case Fans to Single PWM Fan Header?

Ryflick

Reputable
Jun 23, 2019
52
1
4,535
Heya all, I'd like to ask is it safe to connect 3 case fans to a single SYS_FAN1 Header in my motherboard?
My specs :
Processor : AMD Ryzen 5 PRO 4650G
Motherboard : MSI B450M-A PRO MAX AM4
GPU : MSI Radeon RX 570 ARMOR MK2 8GB OC GDDR5
RAM : Netac 2x8GB SR 3200MHz CL16 DDR4
SSD : ADATA SU650 480GB SATA III
HDD : Seagate Barracuda 1TB 7200RPM SATA III
Case : Standard case labeled as "BRIZZ" , have 2 front side fan slot 2 x 120mm and 1 back side fan slot 1 x 80mm
Current fans : cheapo 80x80x25mm fan (back side) and 2x 120x120x25mm fans (front side), all of them using Molex connectors

Currently what I'm trying to do is connecting 3 fans to a single SYS_FAN1 PWM header through my motherboard.
I'm not sure if it safe or not because my PC is currently using a standard Molex connector fans (idk it rated on 1200rpm, maybe?), and my PC is really hot right now, CPU is reaching up to 75°C / 167°F and my GPU is reaching 85° C / 185°F.
Apparently I assume my fans isn't good enough to push & pull air from my chassis, cuz' I don't feel much air going through all of the fans I use.

Any kind of recommendations would be very helpful for me, also if you have any recommendations with Molex-pin fans with good airflow/CFM let me know, thank you!

Oh yeah also I live in South-East Asia (Indonesia), and my place temperature usually 25°C/77°F - 30°C/86°F, I don't know why my PC went very hot and it often shuts down itself (I strongly assume due to overheating).

Thanks again!
 
Solution
You're going to be better served by investing in a new case, with a proper airflow path. The existing case is poor in the airflow and thermals department unless you're interested in a bbq session. The current cases airflow is obstructed with the front fascia. Adding 4 fans won't overcome the obstruction.

You should also look into a reliably built PSU if you want to protect your investments in your budget build. A reliably built unit will save you the hassle of blown components(and headaches when troubleshooting).
Before you strap the fans onto the case, might want to include images of the case you're working with. Often times if the case is badly designed yet has multiple locations to mount fans to, it doesn't matter since badly designed cases tend to have bad airflow regardless of having the best fans in the market slapped onto them(case).

If the fans are all molex connectors, how are you going to connect them to a SYS_FAN header?
 
Short answer is Yes, but you'd better use a product specially designed for that purpose like this

pwm_fan_hub_1.jpg
 
  • Like
Reactions: Ryflick
Before you strap the fans onto the case, might want to include images of the case you're working with. Often times if the case is badly designed yet has multiple locations to mount fans to, it doesn't matter since badly designed cases tend to have bad airflow regardless of having the best fans in the market slapped onto them(case).

If the fans are all molex connectors, how are you going to connect them to a SYS_FAN header?
lbQeOY.jpg

P71Jmi.jpg


This is my current setup and what it looks like.

If the fans are all molex connectors, how are you going to connect them to a SYS_FAN header?
Sorry if I made you confused, what I want to say is I currently have plan to buy new 3-pin/4-pin PWM fans and connect 3 fans to a single SYS_FAN header.
 
You're going to be better served by investing in a new case, with a proper airflow path. The existing case is poor in the airflow and thermals department unless you're interested in a bbq session. The current cases airflow is obstructed with the front fascia. Adding 4 fans won't overcome the obstruction.

You should also look into a reliably built PSU if you want to protect your investments in your budget build. A reliably built unit will save you the hassle of blown components(and headaches when troubleshooting).
 
  • Like
Reactions: Ryflick
Solution
But will it run stable and not causing any problems with the fans? do you have any recommendation for good fan with good airflow?

No problem as fans generally draw 0.25A each, so 3 fans are perfectly OK for a header.

Fans are similar, more or less. But keep in mind that fans with fluid-bearing are usually the most preferable for their silent operation and long life.
 
  • Like
Reactions: Ryflick
The limit on multiple fans connected to a single mobo fan header comes from this. MOST mobo fan headers can supply up to 1.0 A max current to the total load on that header. MOST simple fans today pull from 0.10 to 0.25 A max - to be sure, check the label on the fan or the fan specs on the maker's web page.

Lutfij makes very good points above. NOTE that ANY fan connected to a Molex power output connector from the PSU will always run at its full speed. So changing to new fans that can connect instead to the mobo headers can NOT give you more cooling than that UNLESS you change to different fans with much higher max air flow specs. The advantage of mobo headers is that they CAN control the speed of those fans by REDUCING their speed but ONLY if the full-speed fans are doing too much cooling to start with! If you need MORE cooling than you have now you will need fans with more air flow AND likely a better arrangement or better case entirely to make air flow more easily through the case. And don't forget that you need some fans to INTAKE air (usually at the front) and some to EXHAUST air (usually rear and possibly top).
 
You're going to be better served by investing in a new case, with a proper airflow path. The existing case is poor in the airflow and thermals department unless you're interested in a bbq session. The current cases airflow is obstructed with the front fascia. Adding 4 fans won't overcome the obstruction.

You should also look into a reliably built PSU if you want to protect your investments in your budget build. A reliably built unit will save you the hassle of blown components(and headaches when troubleshooting).

Unfortunately I'm very short in budget for upgrading my PSU and buying new PC case, so the only I could afford to do is buying another fans that if possible reducing overheat in my PC

No problem as fans generally draw 0.25A each, so 3 fans are perfectly OK for a header.

Fans are similar, more or less. But keep in mind that fans with fluid-bearing are usually the most preferable for their silent operation and long life.

Okay, thank you! I will search fans using fluid-bearing.

The limit on multiple fans connected to a single mobo fan header comes from this. MOST mobo fan headers can supply up to 1.0 A max current to the total load on that header. MOST simple fans today pull from 0.10 to 0.25 A max - to be sure, check the label on the fan or the fan specs on the maker's web page.

Lutfij makes very good points above. NOTE that ANY fan connected to a Molex power output connector from the PSU will always run at its full speed. So changing to new fans that can connect instead to the mobo headers can NOT give you more cooling than that UNLESS you change to different fans with much higher max air flow specs. The advantage of mobo headers is that they CAN control the speed of those fans by REDUCING their speed but ONLY if the full-speed fans are doing too much cooling to start with! If you need MORE cooling than you have now you will need fans with more air flow AND likely a better arrangement or better case entirely to make air flow more easily through the case. And don't forget that you need some fans to INTAKE air (usually at the front) and some to EXHAUST air (usually rear and possibly top).

I see, I'll reconsider to buy a new better PC case for better airflow.

But in any case do you guys somewhat have any recommendations either using Molex or 3/4-pin PWM fans too? I'll try to spare some money for extra, buying better fans, PSU and case one at a time.
 
[INFO]
Just a quick info guys, I've tested 3 days ago to change my PSU cable
turns out the PSU is having an issue that causing my GPU went overheating and power instability

After I changed the PSU cables it went fine so far and the temperature drops 25°C from around 85°C to max 65°C and no issues