Could one faulty fan cause random fan speeds?

khazad · February 22, 2023

This is my pc, and the fan to the right of the 1080 is almost dead, I was playing Planetside 2 with the fan speed at 100% in MSI Afterburner and after a while I started hearing some rattling inside my pc, I checked the GPU and noticed that the fan was wobbling and spinning a bit slower than the other two, so I exit the game and restarted my pc and in the process of restarting I noticed that the fan speed wouldn't kill itself which normally happens when Windows closes MSI Afterburner, instead it would just keep going between 70 and 100% until windows boots up again and then it would try to go to 100%, so the next thing that I did was to turn off my pc and turn it back on again after a few seconds and noticed that the fan would ramp back up to 100% after a few seconds when Windows already booted up, probably because MSI Afterburner opens up a few seconds later.

What's weird is that whenever I close MSI Afterburner it would just go back to normal speeds and stay around 850rpm with the GPU temp at 50c and the hotspot at 60c but when I open MSI Afterburner it'll stay at 63%, it's probably because of the fan curve but this never happened before, whenever I stop playing I would put the fan speed in auto and it would put it at "quiet" levels but now it wants to stay in 60% or 70% depending on the hotspot. I always try to keep everything cool in my pc at least below 80c, at idle the temps are around 50 and 55c and normally reaches 60c when the room temp is above 30c and that's most of the days now since I'm in the summer and I always use an undervolt profile when I turn on my pc, I don't know if the sensors went bad or its just the two fans that tries to have more airflow now to keep up with the temps since one fan is not working properly.

Also I noticed a few weeks ago that whenever I put the fans at 100% it would take like 5 seconds to catch the fan speed.

Supersonicwolfe · February 22, 2023

10 minutes ago, khazad said:

This is my pc, and the fan to the right of the 1080 is almost dead, I was playing Planetside 2 with the fan speed at 100% in MSI Afterburner and after a while I started hearing some rattling inside my pc, I checked the GPU and noticed that the fan was wobbling and spinning a bit slower than the other two, so I exit the game and restarted my pc and in the process of restarting I noticed that the fan speed wouldn't kill itself which normally happens when Windows closes MSI Afterburner, instead it would just keep going between 70 and 100% until windows boots up again and then it would try to go to 100%, so the next thing that I did was to turn off my pc and turn it back on again after a few seconds and noticed that the fan would ramp back up to 100% after a few seconds when Windows already booted up, probably because MSI Afterburner opens up a few seconds later.

What's weird is that whenever I close MSI Afterburner it would just go back to normal speeds and stay around 850rpm with the GPU temp at 50c and the hotspot at 60c but when I open MSI Afterburner it'll stay at 63%, it's probably because of the fan curve but this never happened before, whenever I stop playing I would put the fan speed in auto and it would put it at "quiet" levels but now it wants to stay in 60% or 70% depending on the hotspot. I always try to keep everything cool in my pc at least below 80c, at idle the temps are around 50 and 55c and normally reaches 60c when the room temp is above 30c and that's most of the days now since I'm in the summer and I always use an undervolt profile when I turn on my pc, I don't know if the sensors went bad or its just the two fans that tries to have more airflow now to keep up with the temps since one fan is not working properly.

Also I noticed a few weeks ago that whenever I put the fans at 100% it would take like 5 seconds to catch the fan speed.

I assume you are referring to fans on the GPU?

I have a 970 Windforce OC. And only one of the fan is providing fan speed feedback, The other two is just using the same setting, no tachometer wire. (typical fans have 3 or 4 pin wires. Power +/- and fan speed sense, plus PWM if its a 4 pin. The other two fan only have power +/- )

It is possible the fan failing is the fan providing fan speed feedback. The fan controller sees it spins slowly so push the fans to maximum.

khazad · February 22, 2023

40 minutes ago, Supersonicwolfe said:

I assume you are referring to fans on the GPU?

I have a 970 Windforce OC. And only one of the fan is providing fan speed feedback, The other two is just using the same setting, no tachometer wire. (typical fans have 3 or 4 pin wires. Power +/- and fan speed sense, plus PWM if its a 4 pin. The other two fan only have power +/- )

It is possible the fan failing is the fan providing fan speed feedback. The fan controller sees it spins slowly so push the fans to maximum.

Yeah I'm referring to the fans.

The GPU uses a PWM splitter and the 3 fans connects to it, but probably the faulty one is the one that has the speed feedback like you said.