HX750 Gold with noisy fan

I bought a new Corsair HX750 (80 Plus Gold certified) power supply last week, and installed it into a computer I built this weekend. I chose a Corsair power supply again because I was very happy with how the HX750 (80 Plus Bronze certified) I bought last year performed.

This time I got a power supply which I suspect may have a defective fan controller. The problem is that the fan (140 mm) goes to what is likely 100% speed at recurring intervals, for no apparent reason. This happens regardless of whether the system is at load or in idle.

During my troubleshooting I monitored all fans (CPU, GPU and chassi) with software and ocular inspection. I then put a 10x10 centimeter (approx. 4x4 inches) piece of folded paper behind the power supply exhaust grid, and listened very carefully. The fan can be heard starting up, turning rather slowly and almost noiseless, and can be heard going to a complete stop (it has some faint chirping sound as it stops). As the power supply fan start up and turn at low speed, the piece of paper stayed upright, but were blown far away as soon as the fan throttles up. When this throttling happens, about every 7-9 minutes (measured), the fan goes to 100% for 2-3 seconds (estimated), and then gradually decrease in speed for another 12-15 seconds (estimated) - often to a complete halt, or to a very low (almost inaudible) speed.

The exhaust air is lukewarm, as is the power supply. IIRC the power supply is supposed to support fanless operation when it is running below 20% load (150W), and I believe the system does run well below 150W in a Windows environment with only a few light applications running.

The dual fans (80 mm) of my graphics card is what normally makes the most noise, as they run at several thousand RPM at full load. As I regularly play games using headphones I know that those two fans can barely be heard, as my circumaural headphones from Sennheiser blocks out a lot of the noise. I also know that the HX750 (80 Plus Bronze certified) I bought last year makes virtually no noise at all.

The recurring noise from the new HX750 easily penetrate my headphones, and is heard well above the rest of the system. With my former experience with Corsair products I find it hard to believe that a fan controller would be so poorly designed in one of your products.

I have been in contact with the company selling the power supply to me, and they confirmed today that they are sending out a return shipping label -- still I would like confirmation from someone at Corsair that the power supply is not supposed to operate like this, before sending it anywhere.

Thanks in advance!

Regards

Daniel

What you have posted would suggest there may be some restriction on the intake for the PSU. Does your case have a filter over the inlet for the PSU? (Assuming that PSU is in the bottom of the case).

I don't think there is anything restricting airflow much, as there are two large honeycombed sections below the PSU, designed to accept 140 mm fans. There is also a large removable plastic dust screen, but removing it makes no difference. The PSU pulls air from outside the case. Inlet air temperature is about 22.1 degrees Celsius/~72 degrees Fahrenheit.

However, The fan is controlled by thermal temp and load on the PSU as it reaches a certain load or Temp internally (about 49 Deg C) the fan will turn on as needed to keep the temp bellow 46 Deg C. If the load is about 40-60% I would expect this to happen more frequent at higher loads 60+% or it may depending on Room Temp stay ruining at or near Full speed.

I have been checking out a few tests of my graphics card, for example this one, and determined that my system does not pull anywhere close to 150W (20%) at idle.

Nevertheless the PSU fan suddenly goes to full speed, independent of system load. As I described it regularly goes to full speed for 2-3 seconds, then goes to a complete halt within 15 seconds. Between those occurences the fan controller seems to regulate between fanless and low speed fan operation, not making noticably more noise than my one year old HX750.

With the system spec you gave I would expect your system load to be about 150-200 Watts at idle and about 450-600 watts at full load. So you are not far off.

My former system (Core 2 Q9550, the same graphics card, 3x mechanical harddrives, two more peripheral cards, one more fan) pulled about 130 Watts at idle, measured with a clamp meter. I got new technology (more efficient) and less components, so there is no way my new computer pulls more at idle.

But what you have described sounds more like normal operation to me. However, if you want to try and replace it I would not object. Please use the link on the left and request an RMA.

Normal operation?

At times it does seem to operate in a way that could be considered normal, with regard to power draw and cooling needs, but intermittently the fan goes to maybe 2000 RPM - regardless of whether the computer runs idle for 1 hour or runs at full load for 1 hour. If we assume that my computer runs idle at 200W consumption (which it most certainly doesn't) it is still below 30% load - why would the cooling fan run at full speed? It does not make sense.

There is no point in replacing the PSU if it's designed to do what it does, which I believe it is not.

I'll run some more tests tomorrow. I will remove the graphics card and the optical drive first, and run with integrated graphics. Next step will be removing the PSU from my chassi and run motherboard, memory and the CPU idle in BIOS/UEFI. Would you consider it being normal if it continues going to 100% fan speed?

Maybe I'll throw in my old HX750 and see how it works. I'll be back! ::pirate::

I have now disconnected and removed my graphics card, running on Intel HD Graphics 4000, but still no improvement regarding the sudden fan surges. :(:

I have frankly never had a PSU that frequently runs so unbearably loud as this one, and considering that I built my first computer almost 18 years ago I can tell that I'm not being picky about a little noise.

I solved it by sending my unit back and got a full refund from my retailer.

I discovered that the PSU did run passively as it is supposed to, at least according to the marketing, while mounted upside down (fan up) or outside the chassi. With the PSU mounted in its correct position (fan down) the fan controller is likely triggered by heat building up in some spot near a thermal sensor, which in turn activates the fan. The problem is that whenever the fan needs to run, the fan controller starts with 100% fan speed (like cooling fans do on many laptops) -- which is really a disaster from a silent design standpoint.

During my attempts to find a solution I have come across a great many forum threads written by people with the exact same issues, so this is not a question of a single defective unit. This is by design.

I feel sorry for Corsair because of the impact that these problems will undoubtedly make on your reputation, but hope you have the resources to set things right.

I can send you the serial number of the PSU and all the other information on the stickers to you if you want to, but I don't think you need my unit for testing since this is most likely a design issue.

I solved it by sending my unit back and got a full refund from my retailer.

 

I discovered that the PSU did run passively as it is supposed to, at least according to the marketing, while mounted upside down (fan up) or outside the chassi. With the PSU mounted in its correct position (fan down) the fan controller is likely triggered by heat building up in some spot near a thermal sensor, which in turn activates the fan. The problem is that whenever the fan needs to run, the fan controller starts with 100% fan speed (like cooling fans do on many laptops) -- which is really a disaster from a silent design standpoint.

 

During my attempts to find a solution I have come across a great many forum threads written by people with the exact same issues, so this is not a question of a single defective unit. This is by design.

 

I feel sorry for Corsair because of the impact that these problems will undoubtedly make on your reputation, but hope you have the resources to set things right.

 

I can send you the serial number of the PSU and all the other information on the stickers to you if you want to, but I don't think you need my unit for testing since this is most likely a design issue.

I fear that I totally agree with you... I have my PSU installed fan up for the last 2 days, and the fan takes a lot longer to kick in now... But when it needs to kick in it does at 100% speed. This is not what I consider a *quiet* psu... It would be better if the fan was on all the time. Anyway, it's good to know that other people have the same problem as me, and I'm convinced too that this is a design flaw. I may take back my PSU too and go for a different brand that is actually quiet all the time, despite the fact that the HX series are one of the best out there. It's a shame to see such design errors, for otherwise perfect devices, considering the fact that the old HX serries (the bronze/silver) were flawless and completely silent.

Anyway, Corsair, please take what we say into account, we really value you as a company (amazing products and customer support), but please test the units before shipping them. Both my HX PSUs (650 and 750) were faulty, each in its own way. I am really disappointed by this.

Ram Guy, if this problem is ever fixed (on future units) please let us know, and if I still own my device I'll then RMA it. Thanks for everything, and sorry for hijacking your thread. What I wanted to say fitted here better, so Corsair can see that many of us have the same concerns.

loukas77 & Valid,

I will pass this on to the PSU Product manager as that is about all I can do. But the design was implemented to help with noise at lower loads and to make the PSU's more efficient. I mean at or near full load the fan will be running at or near 100% or generate more noise that is a given. But being able to shut the fan off when its not really needed will help to maintain a more quiet system under light loads. That was the intent of this design from what I understand.

At any rate thank you both for taking the time to post your feed back and we will consider it.

Thank you very much Ram Guy, I really value your help and I hope that you pass our thoughts.

What we are talking about here is not fan noise on "nearly full load". We are talking about noise when the fan starts spinning. As you said to me this is when 40% load occurs (though on the box it says 20%). However, the fan does not start spinning quietly. That's what disturbs us (and, I say again, the HX650 did not behave that way, the fan was always quiet).

Yes, the PSU is COMPLETELY silent at low loads (great). Yes, the PSU is VERY silent at high gaming-stressing loads (amazing). It is noisy at the time between those 2 phases (bad).

I have to admit that now that I have it fan up (not the way my case is designed though) the fan almost never spins. I was gaming for about an hour before it kicked in (at full-noisy speed, of course...). And that's why on my thread I said that I believe my fan is not load controlled and only temp controlled. Fan facing down it only took 5-10 minutes before it started. We are not complaining about the fan spinning. We are complaining about the fan spinning at 100% speed when it starts at minimal loads. Please make this clear to whoever you pass these information. If this is ever fixed or redesigned, or anything, please inform us. And again, thank you very much.

We that is a different issue than what the O.P. Posted but yes I agree and this issue you are talking about in this quote we have addressed and have fixed the issue.

I have made myself a Holidays gift and bought a new rig. cause i have 3 graphics cards, 2gtx 670 for octane rendering and a gtx 650 for my displays, and some more stuff i baught a good but quite expensive PSU. the corsair hx750. the reseller told me it is one of the best and most silent, but....this fan issue makes me CRAZY. i have the windforce 670 and they are silent. nothing to hear from them. the whole pc is silent, but that fan, that comes all 2 or 3 minutes, is making me CRAZY. you wrote you have fixed that. please.........tell me HOW. i cant stand this. my cable management was done in 3 hours and made very fine, for a good airflow. i am really NOT interrested to pull all my cables out again. please tell me how to fix it.

kind regards Chris!