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AX1000 fan randomly revs up on idle


gatotsu
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Hi,

 

I've recently built a system with the AX1000 power supply and I do not like that when my system is idle or performing low power tasks (word processing, surfing the internet, etc.) the power supply fan starts up. When the fan starts up it makes a loud revving sound, then stays on for a bit then the fan turns off.

 

It occurs randomly and I've tried the PSU in both orientations as I've seen a user with a Meshify S2 having a different problem in another thread, and the PSU still revs up in both orientations.

 

When gaming my PSU fan stays off, I assume the load is not enough for the fan to stay spinning constantly but it does rev up randomly for a bit, but with the game audio it is difficult to hear, I'm not particularly bothered if it revs up when I'm gaming, it's when my PC is idle or I'm performing low powered tasks the noise bothers me.

 

One solution is disabling the zero RPM fan mode where the fan spins constantly but it's the most audible fan in my system and I can easily hear it, I do not think this is ideal for a 300 dollar PSU.

 

I've seen some other people mention this issue on the internet and I'm wondering if it's specific to this PSU. Do you think there is any possible fix? I could be wrong but I do not think that the PSU is getting warm enough for the fans to rev up. My previous PSU was from another manufacturer and it had a zero RPM mode which was perfectly functional.

 

Should I just get a HX1000 or something?

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Hi,

 

I've recently built a system with the AX1000 power supply and I do not like that when my system is idle or performing low power tasks (word processing, surfing the internet, etc.) the power supply fan starts up. When the fan starts up it makes a loud revving sound, then stays on for a bit then the fan turns off.

 

It occurs randomly and I've tried the PSU in both orientations as I've seen a user with a Meshify S2 having a different problem in another thread, and the PSU still revs up in both orientations.

 

When gaming my PSU fan stays off, I assume the load is not enough for the fan to stay spinning constantly but it does rev up randomly for a bit, but with the game audio it is difficult to hear, I'm not particularly bothered if it revs up when I'm gaming, it's when my PC is idle or I'm performing low powered tasks the noise bothers me.

 

One solution is disabling the zero RPM fan mode where the fan spins constantly but it's the most audible fan in my system and I can easily hear it, I do not think this is ideal for a 300 dollar PSU.

 

I've seen some other people mention this issue on the internet and I'm wondering if it's specific to this PSU. Do you think there is any possible fix? I could be wrong but I do not think that the PSU is getting warm enough for the fans to rev up. My previous PSU was from another manufacturer and it had a zero RPM mode which was perfectly functional.

 

Should I just get a HX1000 or something?

 

The HX1000 is a MUCH BETTER PSU with a MUCH BETTER fan controller.

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I'll probably pick up a HX1000 because it's been on the market for some time, well reviewed and well received by the enthusiast community. Now that I think about it, despite the inferior efficiency (which probably doesn't matter), the HX1000 is a multi-rail unit which offers another layer of protection.

 

I do feel like an idiot now because I did a lot of research before buying the AX1000, I've seen great praises from Aris @ Tom's Hardware and Cybenetics data showed the AX1000 as being excellent in almost every aspect. Don't get me wrong, the AX1000 is pretty great, it's stable, no coil whine issues, it's just that the fan revving noise is really annoying.

 

It's past Corsair's return window and the warranty replacement won't make sense for me because it's likely that the replacement unit will have the same behavior. I may have to count this as a loss and purchase another unit. I do feel a bit cheated because Corsair does advertise the AX1000 as 'ultra-low-noise' but that clearly isn't the case here.

 

I'm getting the HX1000 because I won't need to replace cables as they're the same type-4 cables according to what I've read.

 

/rant

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The HX isn't really "inferior quality". I argue it's actually better quality. Just some inferior performance. But the differences in that respect are negligible (e.g. efficiency, voltage regulation, ripple/noise).
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Do you mind giving me a brief overview of why you'd argue that the HX1000 is better? I opened up a ticket with Corsair and they're willing to exchange my PSU for a HX1000. However, if you do not wish to reply based on your position at Corsair that's fine too.

 

Also what causes the AX1000 fans to spin up? Is it thermals and/or load? I don't think I've ever done anything to my PC for the fan to spin up constantly. I've tried stress testing the CPU and GPU and the PSU still stays silent when it doesn't rev up randomly. I didn't take a look at the watts being drawn from the wall.

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The fan controller in the AX is very basic. The non-Seasonic built Corsair PSUs use an MCU that controlls the fan with either load, temperature and has a built in hysteresis to bring temperatures down below the temperature threshold that requires active cooling so the fan does not "pulse".

 

As for the performance: Just check out any review from Aris (TechPowerUp or Tom's Hardware) or simply pull up the Cybebetics reports for either.

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As the owner of the OEM sibling model of that AX1000 (4 of them actually), I understand what you mean. The fan turn on from zero mode is both watt and/or temperature triggered. It's not hard to get into that zone in Summer months. Also, like almost every PSU out there it needs to do a 12v start-up for the fan when it powers on. That is very noticeable and it catches me off guard every time. There is something shrill about it, perhaps from the type of grill used. The lowest fan speed with zero mode disabled is not exactly quiet, at least compared to the AX1200i that is in there now.

 

With AXi/HXi PSUs the fan can sit on 750 rpm all day long and I can't hear it at idle. You will get manual control over the fan on the HXi and be able to set your own preferences. However, be aware all of these will do the full power fan start when you first power on the PC, but then not again.

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As the owner of the OEM sibling model of that AX1000 (4 of them actually), I understand what you mean. The fan turn on from zero mode is both watt and/or temperature triggered. It's not hard to get into that zone in Summer months. Also, like almost every PSU out there it needs to do a 12v start-up for the fan when it powers on. That is very noticeable and it catches me off guard every time. There is something shrill about it, perhaps from the type of grill used. The lowest fan speed with zero mode disabled is not exactly quiet, at least compared to the AX1200i that is in there now.

 

With AXi/HXi PSUs the fan can sit on 750 rpm all day long and I can't hear it at idle. You will get manual control over the fan on the HXi and be able to set your own preferences. However, be aware all of these will do the full power fan start when you first power on the PC, but then not again.

 

Actually, the Seasonic units' fan controllers are not load based. You need OPAMPS to measure current and an MCU to report to and they didn't want to re-lay out the PCB to accommodate those or spend the extra money. Their fan is only temp based. Like most other PSU companies, they use load instead of temp to graph the fan curve, but that load is based on a constant 25°C temperature. In other words, they test in a 25°C room, increase the load to heat up the PSU temperature, the fan spins up and they plot the point. Nothing more.

 

As for the high starting RPM: That is because Seasonic uses the DC version of the fan and not the PWM version. The DC version requires, as you state, a minimum voltage to start spinning. With PWM, you just reduce the pulse width so you can reduce the starting voltage. But alas, you need a PWM controller and Seasonic didn't want to spend the extra 15 cents for that part. So that's another reason why the fan is louder.

 

As for the "full speed startup": It's only the AXi that did that. It does that to measure the fan curve to reprogram the MCU. But then we (Corsair) learned that wasn't really necessary and that the fans don't differ that much from one to the other (given that all other things are equal), so the HXi and newer Zero RPM fans do not "rev up". They only do an initial test spin that shows the fan is working and that's only about 650 RPM for about three seconds. You can't hear it.

Edited by jonnyguru
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Yeah the fan noise sometimes make me jump :[pouts:

 

I previously thought that it was not getting warm enough for the fan to rev up but now that I think about it, the PSU is in a shroud and is isolated from the rest of the components which may cause the heat to build up after a while.

 

I'm fine with the PSU making a start up fan noise at boot.

Edited by gatotsu
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  • 4 weeks later...
The HX1000 is a MUCH BETTER PSU with a MUCH BETTER fan controller.

 

I'm sure that's why the AX is rated at 80 Plus Titanium, whereas the HX is 80 Plus Platinum.

 

But I agree about the fan controller; I've been getting the fan revving too, during gaming, now and then. I wasn't sure which fan it was, until today (I have 8 case fans and 13 in total). System isn't very audible though at idle, and since I am running an Obsidian 1000D, the PSU is hidden away under a shroud, which means I don't hear it at all if I turn off the Zero RPM mode.

 

So I guess I'll just run the fan all the time. My Corsair HX 750 lasted for 12 years with the fan running constantly - and it still runs, but the fan has started to make some slight wear noises.

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I don't quite understand the context of this.

 

Titanium, Platinum, etc. are levels of efficiency. Nothing more.

 

I know.

 

I guess since you're a PSU guy, I can ask you. I've disabled the zero RPM mode on my AX 1000 now, but it still seems to rev up now and again during gaming. I don't see how that's possible, seeing as the fan should constantly be spinning anyway, and follow some kind of linear curve based on temperature and PSU load. Is the mode button simply broken? Edit: I filmed with my phone, then slid it under the behemoth of a case which I am in no hurry to lay fully on its side (1000D) and filmed with mode button in both positions. Could clearly see the fan was spinning when mode was disabled, and not spinning when enabled. So why would it rev up violently then? My system isn't drawing THAT much power (stock 2080Ti and a stock i9 10900K), even during full load.

 

That said, I don't actually hear any difference in noise when I enable / disable the zero rpm mode (edit: must be because the psu shroud on the 1000D masks the idle fan noise). And the damn thing turned off my PC just now when I disabled the mode again (I didn't touch the power button).

 

I've had several Corsair PSU's and have never had a single issue with any of them. Then I go and buy one in the most expensive lineup, and now I get issues. Go figure. I actually have a zero rpm PSU in my home server too (RM550), and I have never heard a single sound coming from it, ever. Not even when booting it up.

Edited by Sehnsucht
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I know.

 

I guess since you're a PSU guy, I can ask you. I've disabled the zero RPM mode on my AX 1000 now, but it still seems to rev up now and again during gaming. I don't see how that's possible, seeing as the fan should constantly be spinning anyway, and follow some kind of linear curve based on temperature and PSU load. Is the mode button simply broken? Edit: I filmed with my phone, then slid it under the behemoth of a case which I am in no hurry to lay fully on its side (1000D) and filmed with mode button in both positions. Could clearly see the fan was spinning when mode was disabled, and not spinning when enabled. So why would it rev up violently then? My system isn't drawing THAT much power (stock 2080Ti and a stock i9 10900K), even during full load.

 

That said, I don't actually hear any difference in noise when I enable / disable the zero rpm mode (edit: must be because the psu shroud on the 1000D masks the idle fan noise). And the damn thing turned off my PC just now when I disabled the mode again (I didn't touch the power button).

 

I've had several Corsair PSU's and have never had a single issue with any of them. Then I go and buy one in the most expensive lineup, and now I get issues. Go figure. I actually have a zero rpm PSU in my home server too (RM550), and I have never heard a single sound coming from it, ever. Not even when booting it up.

 

With pretty much every Corsair PSU, Corsair's engineering team is allowed to do...well... engineering.

 

But when working with Seasonic, Corsair's hands are a little more tied. As I said in my previous post, the fan controller is not as fine tuned as other Corsair PSUs.

 

At least Seasonic let Corsair pick their own fan motor, so there isn't the low RPM motor noise that some users experience with the similar PSUs using the same model fan.

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With pretty much every Corsair PSU, Corsair's engineering team is allowed to do...well... engineering.

 

But when working with Seasonic, Corsair's hands are a little more tied. As I said in my previous post, the fan controller is not as fine tuned as other Corsair PSUs.

 

At least Seasonic let Corsair pick their own fan motor, so there isn't the low RPM motor noise that some users experience with the similar PSUs using the same model fan.

 

I thought the Seasonic PSU's were some of the best on the market. I wish some of the reviews I checked out had mentioned this annoying fan issue. Tempted to toss it in the trash now and get an HX1000 instead. Thanks for replying.

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