Question If all fan headers are used, some fans don't work.

Angolmagyar

Honorable
Jul 8, 2014
50
0
10,540
2
So this is a weird one, on my Aorus Z390 Pro there are 8 fan headers.
CPU_FAN
CPU_OPT
SYS-FAN1
SYS-FAN2
SYS-FAN3
SYS-FAN4
SYS-FAN5_PUMP
SYS-FAN6_PUMP

I am using 9 fans in my CoolerMaster H500M case, with 2 of those fans being part of a Corsair AIO, so those 2 are not directly plugged in the motherboard. However, if I do decide to populate 7 or 8 of the fan headers, some fan(s) will either stop working or I lose control over them within the OS (including the BIOS).

I have tried individually connecting the fans, rebooting and seeing the results and up until 6 fans, doesn't matter which fans or which headers they are, they work. But as soon as I plug in a 7th and/or 8th, one or more (up to 3 from my experience) fans will either stop working altogether, or I lose control over their speed from software.

Now, since I have checked every header and every fan individually, I can confirm that neither any fan or header is faulty. So what could the issue be? There should be plenty of power, all of these tests were run at the pc running idle and the PSU is 750 watts.

The full specs are:
Aorus Z390 Pro
Intel Core i7 9700K
Gigabyte RTX 2060 Super OC Windforce
2x8GB Corsair Vengeance RGB Pro 3200MHz C16
Sabrent Rocket 1TB NVMe SSD
WD 1TB HDD 7500RPM (Green, i believe... its old)
Seagate Barracuda 3TB 5400RPM
CM H500M case (includes 2xMF200R + 1x140mm CoolerMaster (non rgb & non LED) fans)
Cooler Master MF120R fan
Corsair Hydro 100i RGB Platinum AIO (with included fans)
3xBlue LED 120mm case fans (from my old case) rated at 0.45 amps
Corsair HX750i 80+ Platinum PSU

I also have a wifi card, a PCIe to internal USB 3.0 header card, and.... thats it, as far as I remember and can see... I like to load up my stuff well xD

Anyways, with all of these components, the PSU should have no problem powering all the fans, I even had my old GTX 750 Ti in there for a while and again, power was no issue. So why could my fans be acting up like this? I can still run all of my fans, as I have a 10 port PWM fan controller powered by sata, which I plugged the 3 blue LED fans into and now they run fine, but at full speed without control (they are DC fans, not PWM). It's not a big issue, my temps are just fine even in the heat of summer, just this behavior is strange and new to me, I've never come across such an issue before.

Thanks for any tips in advance!
 
Last edited:

Angolmagyar

Honorable
Jul 8, 2014
50
0
10,540
2
You need to go beyond just "750 watts".

Make and model PSU? New, used, refurbished?

Look on the PSU and determine what wattages are available by voltage rail.

For example:

https://graphicscardhub.com/what-psu-do-i-have/

And especially scroll down to "How to Read PSU Label / Sticker".

Ensure that your PSU can indeed support your builds power requirements at all voltages and beyond "idle".
The PSU is listed in the full specs in my original post, its a Corsair HX750i

Wattages per rail listed in the pic below, found on: https://www.anandtech.com/show/8835/corsair-hx750i-power-supply-review



Hope this helps. Thanks!
 

Angolmagyar

Honorable
Jul 8, 2014
50
0
10,540
2
Will the fans beyond 7 or 8 that "stop working" start working if you give them a push?

Maybe not enough startup voltage.
They do not. I can spin them manually as i want, I even used compressed air (not to see if it kickstarts it, just for fun :D ) and it doesn't start up. Wanna add that when I say sometimes I lose control over them rather than have them not work at all, I mean the fan is spinning at some speed and it cannot be changed. Not through bios or in OS utility.
 

Ralston18

Titan
Moderator
Do not spin for "fun".

You can cause bearing damage etc...

Do you have the motherboard's User Manual

I found the following link:

https://download.gigabyte.com/FileList/Manual/mb_manual_z390-aorus-pro_wifi_1001_190708_e.pdf

Verify that the link is a match for your motherboard.

Fan headers are shown and discussed beginning on physically numbered Page 17.

Fan controls are discussed on physically numbered Page 32.

Double check you control configurations.

Not sure what else to suggest.
 
Sep 2, 2020
13
0
10
0
I am having almost the same problem with that same mobo. The only difference is that I am only using 6 fans and 1 cpu cooler pump. Just randomly some of the ports will shut off power to the fans. If it chooses the cpu cooler pump one, I am screwed and have to shut down. I have already replaced the mobo and the 2nd one has the same problem. Also just wasted money upgrading from an 850w bronze psu to a 1000w gold. Didn't fix it. I am stumped and frustrated.... Did you ever get this figured out?
 

Angolmagyar

Honorable
Jul 8, 2014
50
0
10,540
2
I am having almost the same problem with that same mobo. The only difference is that I am only using 6 fans and 1 cpu cooler pump. Just randomly some of the ports will shut off power to the fans. If it chooses the cpu cooler pump one, I am screwed and have to shut down. I have already replaced the mobo and the 2nd one has the same problem. Also just wasted money upgrading from an 850w bronze psu to a 1000w gold. Didn't fix it. I am stumped and frustrated.... Did you ever get this figured out?
Nah, never got a fix... I ended up just using a fan hub I had before, and plugging 3 fans into that, powered by sata. No problems after that at all, its just a shame that i can see the 3 fan header pins on the mobo, so empty and no control over those 3 fans :( .

Sorry I'm no help here, but if you manage to figure it out, please let me know!
 
Sep 2, 2020
13
0
10
0
Nah, never got a fix... I ended up just using a fan hub I had before, and plugging 3 fans into that, powered by sata. No problems after that at all, its just a shame that i can see the 3 fan header pins on the mobo, so empty and no control over those 3 fans :( .

Sorry I'm no help here, but if you manage to figure it out, please let me know!
Thanks man. I did not figure it out and it seems the more different things I try, or each day that goes by, it gets worse. I called newegg again and I am returning the mobo and cpu again. This time I am just getting something different entirely. A z490 msi gaming carbon mobo with a 10850k. Hopefully I don't have any similar issues. If I do, i would venture to say that newegg is peddling damaged/used boards somehow. Fingers crossed.
 

Angolmagyar

Honorable
Jul 8, 2014
50
0
10,540
2
Thanks man. I did not figure it out and it seems the more different things I try, or each day that goes by, it gets worse. I called newegg again and I am returning the mobo and cpu again. This time I am just getting something different entirely. A z490 msi gaming carbon mobo with a 10850k. Hopefully I don't have any similar issues. If I do, i would venture to say that newegg is peddling damaged/used boards somehow. Fingers crossed.
It's not newegg, i bought my motherboard and cpu on amazon, and they both (and every other component i have) work perfectly as intended with the exception of this fan issue.... its strange, it must be a design flaw or something, especially if you had 2 separate boards behaved like this, plus mine... I'd wager there are other Z390 Pro users out there who have this issue... Either way, my mobo and case currently runs 9 case fans, including the AIO fans, which is pretty overkill xD It worked just fine without the 3 I added, and even those 3 I only added because the 3 fan headers are in my line of sight through the glass side panel and I just wanted to populate them... purely cosmetic.. probably damaging my cooling as well, beacause the fans I added can only spin up to 1800 rpm while the fans underneath them can go up to 2000+ rpm.. either the POS blue fans are getting damaged or the 2 corsair and 1 cooler master fan are (I'm not sure if the faster spinning ones or the slower spinning ones, but the mix of the 2 types damages one of them if not both)..

But I digress, I doubt its newegg's fault.. I'll buy some matching fans for the outer top side of my case to match the ones underneath and I'll try all 9 fans on the motherboard that way and see if there is a difference, but like I originally mentioned in this forum post, it didn't matter what was plugged in and what wasn't, if more than 6 fans are plugged in directly into the motherboard, 1 or 2 fans either didn't spin at all, or spun at a constant random speed that I couldn't change, not from OS software, not from BIOS, so I don't think the POS DC fans are the problem....

Actually, on that note what fans do you have plugged in? Do you have only PWM fans or only DC or a mixture like me? I wonder if the mixing of DC with PWM fans make the motherboard misbehave...
 

ASK THE COMMUNITY

TRENDING THREADS