Question Anyone run into this kind of issue with fans like this before?

[Xyele-]

I just built a new system this weekend, and also a Phanteks G500A DRGB case. My motherboard is an MSI PRO Z690-A WIFI, board, and I installed a DeepCool LT720 AIO.

The fans are Phanteks M25-140 DRGBs (PWM)

The case came with the 3 front fans, so all I had to do for those was connect the 4 pin fan header to my mobo to control the speeds, and they seem to be going down to what they should be, I have them set to 50% @ 40C on the low end, so they are idling at about 896RPM or thereabouts according to to HWinfo, so I have those connected to Sys_Fan_2, and the highest I've seen them rev is 1400RPM, while the rear fan went fully to 1800RPM under a benchmark.

The rear fan I installed took me a few minutes to figure out how to connect it to the case RGB daisy chain, once I found the 3 pin to connect it to, and then connected the 4 pin to the mobo, Sys_Fan_6 in this case.

Once I went into the bios and set my curves, I noticed that even set the same as the front 3 fans (which are all one header), it's spinning at 1160-1180RPM instead of lower, I did move the setting in the bios and it does slow down if I change it (if I go lower than 50% I can get it close to the front fans speed), but the same model fan set exactly as the front fans on a different header just a higher RPM, seems more like it's running closer to 60% or so instead of 50%.

I'm certain the 3 pins on the fan are just for daisy-chaining RGB to the phanteks controller, and the single 4 pin would go to the motherboard, unless I missed something.

I tried a different fan in two different headers (had a Noctua 140mm fan so I tried it in different headers, same result), same issue, so is this just some weird issue with the fan headers, or has anyone else run into anything similar before? Not a huge issue since they seem to ramp up and work, just curious if that's something that's normal.

 

[JohnBonhamsGhost]

haven't gone through many of the latest MSI BIOS in a bit but there may be more options regarding controlling the fan headers.

some can have separate options for each motherboard header such as; Turbo, Balanced, Quiet, etc...
if these exist, make sure they are all set to the same option.

 

[Paperdoc]

Two suggestions to check.
1. The MODE setting should be PWM, not Voltage or DC or Auto.
2. IF each SYS_FAN header has a choicce of which TEMPERATURE sensor to use, ensure it is using the same one on the MOTHERBOARD, not the one inside the CPU chip.

 

[Xyele-]

Thanks much for the replies. I made sure all the fans were set to PWM after setting them up and setting up the curve, all going off the same sensor.

It's weird how the front fans (which are daisy chained to the phanteks controller for rgb and connected to one header, and the rear fan a seperate header, decided against using the mobo rgb for now) go down to 880RPM, but at full speed they stop at ~1400 (fans are rated at 1800RPM), but the rear still shows 1150, but it will ramp up to 1800RPM when needed, unless that's from a power draw limit.

AIO cooler works as it should, pump I have at 100% and fans are on a curve and ramp up and down as they should (fans and pump connected to proper headers).

So I'm starting to think either the mobo is wonky, or the RPMs just aren't being registered correctly (I tried testing by switching between the different sensor options for temperature, no change) because even the noctua fan I bought to use before my rear fan arrived was doing the same.

So I'm not sure at this point, but that being the only issue I can see, I think it'll be easier to just let the rear fan run the 300 or so RPM faster than the fronts, just an odd one that I haven't seen before.

 

[Paperdoc]

Just to verify: is the REAR fan that runs at a different speed the SAME model as the three front ones? Fans of different design DO run at different speeds when sent the SAME speed control signal. The control system does NOT try to run to a specific SPEED, even though we all talk of "speed control". It targets the TEMPERATURE at a selected sensor, and alters the fan speed to whatever it takes to reach that temp.

 

[Xyele-]

Just to verify: is the REAR fan that runs at a different speed the SAME model as the three front ones? Fans of different design DO run at different speeds when sent the SAME speed control signal. The control system does NOT try to run to a specific SPEED, even though we all talk of "speed control". It targets the TEMPERATURE at a selected sensor, and alters the fan speed to whatever it takes to reach that temp.

Yep, the G500A comes with 3 pre-installed M25-140 D-RGB fans in the front, so I bought the same to install in the rear, so all are the same model and brand fan, I've change the temperature source to different things with no change, so I'm thinking that's just how these work, they do their job, so that's the main thing.

 

[atchard]

Yep, the G500A comes with 3 pre-installed M25-140 D-RGB fans in the front, so I bought the same to install in the rear, so all are the same model and brand fan, I've change the temperature source to different things with no change, so I'm thinking that's just how these work, they do their job, so that's the main thing.

I had basically the same issue, down to the RPMs. I had the 3 preinstalled from the G500A, and got 4 more, 3 for the top, 1 for the back. Those 4 are one 1 header, while the 3 preinstalled are on another. Was wondering what was up with the speeds, and saw your post, so decided to reach out to Phanteks.

They said the preinstalled fans perform at lower speeds, and are "not comparable to the m25 fans if you were to purchase by itself." They said they'd send the full speed fans to replace, but you'd need to share the invoice for buying the case, then remove the fans, and cut the wires, sharing a picture of that too.

So I guess the answer is they can somehow bin them, or have a limiter of some sort internally. Not sure why they'd differentiate them that way, can't be much money they'd save, and seems a little strange to receive 3 fans, that have stated specs on their data sheets, and then find out they are actually gimped versions. But like you said, they perform well enough, and I'm running them much lower than max speeds anyways, so it works fine I guess, just have to set the curves differently.

 

[Xyele-]

I had basically the same issue, down to the RPMs. I had the 3 preinstalled from the G500A, and got 4 more, 3 for the top, 1 for the back. Those 4 are one 1 header, while the 3 preinstalled are on another. Was wondering what was up with the speeds, and saw your post, so decided to reach out to Phanteks.

They said the preinstalled fans perform at lower speeds, and are "not comparable to the m25 fans if you were to purchase by itself." They said they'd send the full speed fans to replace, but you'd need to share the invoice for buying the case, then remove the fans, and cut the wires, sharing a picture of that too.

So I guess the answer is they can somehow bin them, or have a limiter of some sort internally. Not sure why they'd differentiate them that way, can't be much money they'd save, and seems a little strange to receive 3 fans, that have stated specs on their data sheets, and then find out they are actually gimped versions. But like you said, they perform well enough, and I'm running them much lower than max speeds anyways, so it works fine I guess, just have to set the curves differently.

Interesting to know.

I've just noticed with the fan curves set on my for different temps the front fans spin down to 880ish for the low end and ramp up like they should for higher temps. The rear fan I bought seems to just hang at 1100ish no matter what it's set at for temperature and then ramps up to it's full speed for higher temps.

Very interesting about the difference in fans they use. Although in my case I did try a noctua fan I had lying around for the rear with the same results, and even with the temp set to CPU it was still moving at 1100 ish idle, so maybe that's just normal for those higher rpm fans or something.

But that is very odd to not to include better fans that you'd get just by buying them separately given the price of the case, very weird decision on their part.

 

[Nwik]

Sorry to dig this thing up.
It's a bit unrelated but, I'm thinking of getting a G500A with an extra M25 140mm for the back.
Is the cable long enough to daisy chain it to the front ones or did you had to get an extension cable?
If you needed an extension can you tell me which one did you get?

 

[Xyele-]

Sorry to dig this thing up.
It's a bit unrelated but, I'm thinking of getting a G500A with an extra M25 140mm for the back.
Is the cable long enough to daisy chain it to the front ones or did you had to get an extension cable?
If you needed an extension can you tell me which one did you get?

I didn't have to get an extension myself, it was long enough to daisy chain into the rest of the case fans running it underneath the motherboard towards the back of the case, there is an extension for it, but I didn't need it, motherboard connector is just long enough to reach a fan connector on the board if it's close enough to the rear, and then the RGB is just long enough to reach under from the chain to the rear fan, might take a little readjusting of wires, but definitely doable.

 

[Nwik]

I didn't have to get an extension myself, it was long enough to daisy chain into the rest of the case fans running it underneath the motherboard towards the back of the case, there is an extension for it, but I didn't need it, motherboard connector is just long enough to reach a fan connector on the board if it's close enough to the rear, and then the RGB is just long enough to reach under from the chain to the rear fan, might take a little readjusting of wires, but definitely doable.

Thank you.