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HX650 fan spins up/down when idle


mrl72
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I just bought a used but in like-new condition HX650 PSU. When the PC is idle, the fan spins up/down in a cycle as such:

 

On for 10 seconds. Off for 15 seconds.

 

PC temp at the time when idle is: 35C.

Connected devices: 120mm CPU fan, GTX 1080, SSD.

 

Under load, the fan cycles similarly but more frequently (meaning it doesn't run non-stop, it will spin up/down without a delay in between cycles).

 

I'm aware this PSU has "smart" fan control so I'd like to know if this is normal. If this is by design it is terribly annoying so is there a way to keep the fan constant at a minimum?

 

Thanks!

Edited by mrl72
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I resolved this issue. In case anyone stumbles onto this looking for answers to the same problem, I fixed it by repositioning the psu away from the video card which was pushing a little heat toward the psu causing the fan to cycle on and off. Personally, I think this is a flawed design by Corsair as that should not happen. And anyway maybe they fixed that in recent versions.
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Where do you have the PSU intake? What case is this?

 

As to how it's Corsair's flawed design ... how do you figure? The fan comes on when it gets to a certain temp. If your installation is pushing GPU heat at the PSU ... well, that sounds like an installation issue to me.

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  • 2 months later...

I came back to report that this is ongoing and what I thought solved it initially, hasn't.

 

I've currently got the PC de-cased with the PSU situated far away from the rest of the PC components with nothing around it yet it still constantly spins up and down every 10 seconds or so.

 

Any ideas what is causing this?

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what do you have on it?

TBH, it's a little 650W PSU. A CPU + GPU may create enough load to cause the fans to come on. It cools down a touch, then turns off.

The fan is temperature dependent. So it's likely that you are right at the border point for it to come on ... cool things off ... turn off ... repeat.

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what do you have on it?

TBH, it's a little 650W PSU. A CPU + GPU may create enough load to cause the fans to come on. It cools down a touch, then turns off.

The fan is temperature dependent. So it's likely that you are right at the border point for it to come on ... cool things off ... turn off ... repeat.

 

256GB SSD

GTX 970 GFX card

Bunch of USB peripherals (about 6)

External USB 4TB drive.

 

I use it all day long but have never heard it spin up longer than 10 seconds, even under heavy load (although stuff I do is mainly photoshop so not exactly taxing).

 

It's sitting out in the open air so it's plenty cool, which as you say maybe it's TOO cool to spin up for longer times. But then again it did the same thing in the case.

 

The constant on/off cycling is more annoying than if it was running a constant speed.

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  • Corsair Employees
It's the Gold series.

 

Ok. So that's about an 8 to 10 year old PSU.

 

There is no hysteresis built into the fan controller's programming back then.

 

Not until 2013 did Corsair implement a hysteresis into the fan controller.

 

Without this, the fan will only trigger at thermal and load thresholds. What happens if your PSU is on the precipice of either is the fan "pulses" because it doesn't know if it should start or stop.

 

The added 20 minute hysteresis brings the PSU temperature down so much lower than the thermal threshold that the fan should not spin again for some time.

 

The only time we've seen this since then is recently with the advent of all of these RGB devices. The +5V and +3.3V use load only for fan control. So even if the thermals are low, if the load is high on these non-primary rails, the fan spins up "for no reason". But those are real corner cases when people have A LOT of USB, RGB, etc. on these rails. 99% of the time, 90% of your power is coming from just the +12V rail.

 

Now, I'd like to add that this shouldn't happen when the PC is "idle", because that would be a relatively low load. It must be on the thermal threshold for the fan to start. But you said you tried this both inside and outside of the case and the behavior is the same. So unless it's 35°C in the room you're using this in, then it could just be that the fan controller is "broken". Maybe that's why the guy was selling an otherwise working PSU?

Edited by jonnyguru
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Ok. So that's about an 8 to 10 year old PSU.

 

There is no hysteresis built into the fan controller's programming back then.

 

Not until 2013 did Corsair implement a hysteresis into the fan controller.

 

Without this, the fan will only trigger at thermal and load thresholds. What happens if your PSU is on the precipice of either is the fan "pulses" because it doesn't know if it should start or stop.

 

The added 20 minute hysteresis brings the PSU temperature down so much lower than the thermal threshold that the fan should not spin again for some time.

 

The only time we've seen this since then is recently with the advent of all of these RGB devices. The +5V and +3.3V use load only for fan control. So even if the thermals are low, if the load is high on these non-primary rails, the fan spins up "for no reason". But those are real corner cases when people have A LOT of USB, RGB, etc. on these rails. 99% of the time, 90% of your power is coming from just the +12V rail.

 

Now, I'd like to add that this shouldn't happen when the PC is "idle", because that would be a relatively low load. It must be on the thermal threshold for the fan to start. But you said you tried this both inside and outside of the case and the behavior is the same. So unless it's 35°C in the room you're using this in, then it could just be that the fan controller is "broken". Maybe that's why the guy was selling an otherwise working PSU?

 

Thanks for this, that's all good stuff to know. The seller of the PSU told me he hadn't used it at all, and it did come like-new. Thought it was probably too good to be true. He probably had the same issue and swapped it out.

 

I am running HWiNFO64 and I'm not sure of how accurate the ambient temperature reading is, but it's telling me I'm averaging 39°C in the cabinet it's currently sitting in (it's now inside an Arcade machine with ventilation).

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Thanks for this, that's all good stuff to know. The seller of the PSU told me he hadn't used it at all, and it did come like-new. Thought it was probably too good to be true. He probably had the same issue and swapped it out.

 

I am running HWiNFO64 and I'm not sure of how accurate the ambient temperature reading is, but it's telling me I'm averaging 39°C in the cabinet it's currently sitting in (it's now inside an Arcade machine with ventilation).

 

I don't imagine this arcade machine has an unusually high +5V and/or +3.3V load, does it?

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