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Logic behind the fan starting %100 then slowing down?


Ozgurhx

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Hello. My name is Ozgur. I bought a HX750 gold edition yesterday. I was in need of a PSU since my previous one was giving me system freezes. I checked online and saw that corsair hx750 was given great reviews on newegg and amazon so i made the decision, went out and grabbed one.

 

The PSU's complete silent fan operation mode is VERY NICE. It's been something that i wanted for a long time myself. So thank you for that.

 

However, when it starts spinning, it starts at full speed and slows down from there, which made me VERY upset. I first thought that there was a problem within the unit but after checking online it seems that this is the exact thing that's supposed to happen.

 

So now may i ask; what's the logic behind this? I mean, you advertise this PSU as having very silent operation, you design a feature for this purpose (which again, is very nice), yet when the fan kicks in to keep the unit cool, it starts at max speed, making the unit VERY LOUD, and then slows down from there. Shouldn't it start slowly, and gets faster instead?

 

This is like getting to 200km/h with your car instantly, then slowing down to 30km/h for city cruising :S

 

Didn't you test these PSUs yourself? Didn't you have someone nearby that would question this?

Q&A test room:

"Sir, our PSU is working flawlessly. No sound whatsoever."

"Excellent"

** fan kicks in**

"Where's this vacoom cleaner sound coming from?"

"It's the PSU, sir"

"What? How?"

"We designed it that way. No sound then max sound then no sound again"

"Ok. Prepare for shipping immediately"

 

:rolleyes:

 

Let's say the fan becomes active at 50 celcius and the unit dies at 70 celcius. Instead of 'rushing' the fan to keep it below 50 celcius, why didn't you lower the heat warning limit, and give the fan more headroom to do it's job, but this time SLOWER?

 

I don't get this really. Did starting the fan with low amperage caused problems on your side? Did you find that it lowered its lifespan? I see no practical way to this design flaw. And IT IS A PROBLEM. What's the point of having complete silent fanless operation mode, if the unit will become SO LOUD, that i'll be able to hear it through my headphones? The feature itself and the action follows contradicts with each other. This is like designing an airbag that's full of metal parts, or an eyeglass that doesn't let light pass through at all.

 

It cost me 230$ over here and the shop doesn't get the unit back either. Since there are no problems with it! You spend that much money, come back home to finally settle after days of frustration with your pc (crashes, freezes), put the new PSU in, be happy for a few minutes, just to get shocked by this 'feature'.

 

Definitely not happy. PSU seemed to be 'the' perfect unit i've ever got, but just one annoying thing was enough to break the feeling. :(:

 

I've been doing some tests for the past 10 hours now, in order to lower the interval of this issue. I'll post them in another thread, when it's done.

 

Bummer.

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However, when it starts spinning, it starts at full speed and slows down from there, which made me VERY upset. I first thought that there was a problem within the unit but after checking online it seems that this is the exact thing that's supposed to happen.

Yes, this is correct, when first b powering on or restarting the machine the PSU is just doing it's own self test of the fan. Thats why it does this!

Unless your saying it does this after some time of being powered up or your power usage goes up.

 

The fan speed is determined not only by temp but load also. So if your calling for high power usage quickly, the PSU will react to that. Since you did not fill in your system specs or say if you are overclocking or not, it would be hard to diagnose accurately

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Yes, this is correct, when first b powering on or restarting the machine the PSU is just doing it's own self test of the fan. Thats why it does this!

Unless your saying it does this after some time of being powered up or your power usage goes up.

 

The fan speed is determined not only by temp but load also. So if your calling for high power usage quickly, the PSU will react to that. Since you did not fill in your system specs or say if you are overclocking or not, it would be hard to diagnose accurately

 

You don't seem to understand. I thought my post was pretty clear.

 

Every PSU has to deal with excessive heat this or that way. There are fans in these units so eventually they'll start spinning at some point. That's not the point.

 

The problem is, HX750's fan starts spinning SUPER FAST FIRST, THEN SLOWS DOWN, which makes excessive noise. I'm talking about the actual usage. During desktop, gaming etc, it doesn't matter. Whenever it kicks in, it spins as if it's at full speed.

 

If a PSU is giving signals of heating up, shouldn't the fan inside start SLOW first, THEN keep getting faster and faster to push the required airflow?

 

When you try to open up something you don't give your full power at first right? You give it a shot and if it's not enough then you try harder. This PSU's fan does exactly the opposite.

 

The philosophy behind this decision seem to be like removing heat from the unit as fast as possible so it can go back to it's silent state, which let me say again, is a completely wonderful feature. But even then i still don't get it because the fan doesn't start fast AND stay fast. That way it could have finished it's task much more quicker. This thing start fast but keeps slowing down until it turn itself off.

 

I built a new rig for a good balance between good airflow and silence. HAF X case with Kaze Q12 fan controller and quality fans etc. When in silent mode the PSU is amazing. No sound. Wonderful. But when the fan becomes active, i'm like :bigeyes: everytime.

 

It's like listening to a good music through your headphones and hearing those scary screams once in a while. It's not pleasant.

 

Made this thread so people could contribute to it. Maybe Corsair change this with their next line of products. I don't know. I can't return the unit and this is the way it is so no point in changing it with another one either. I'll either say screw the warranty and change the fan with another one with lower rpm and amperage, or will attach another fan outside of the case to keep things cooler to lower the intervals of the actual fan on the unit becoming active.

 

My cpu fan spins slow and gets faster as the cpu heats up. Same with the gpu. This thing does it opposite...

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I feel your pain OzgurHX. I had a new AX860i (Flextronics) that would spin its fan every 12seconds when it reached 42C up to 800rpm loud for just 1 or 2seconds then back down again for no apparent reason. Also the fan would run the self-test to maximum rpm at boot and out of sleep mode, sounded like a Harrier Jet Fighter taking off. I think all the Flextronics-OEM based Corsair PSUs do this self-test thing. Sent mine back to Amazon and got a plain AX860 (Seasonic) without the i. Its Seasonic based and the fan never spins at all, perfectly silent, brilliant power supply. The fan will spin up if you want it too, by placing in Normal fan mode via a toggle switch on the unit, but even then it runs so slow, cannot be heard. The AX860 Platinum is pure love.:hihi:

 

Try one of the Seasonic OEM-Corsair improved units; they are beautiful for a noise-sensitive environment.

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The problem is, HX750's fan starts spinning SUPER FAST FIRST, THEN SLOWS DOWN, which makes excessive noise. I'm talking about the actual usage. During desktop, gaming etc, it doesn't matter. Whenever it kicks in, it spins as if it's at full speed.My cpu fan spins slow and gets faster as the cpu heats up. Same with the gpu. This thing does it opposite...

It shouldn't work that way. I would have that unit RMA'd. It should start out slow and then ramp up if needed.

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It shouldn't work that way. I would have that unit RMA'd. It should start out slow and then ramp up if needed.

 

My PSU is not faulty.

 

http://forum.corsair.com/v3/showthread.php?t=112022

 

Post #5:

 

...It goes up to full speed and then down to normal. Every single time it needs to start spinning. Please ask an engineer and let me know if this is how it should behave...

 

Staff answer:

 

I just had a quick meeting with Engineering and this is how it should work.

When the system is first powered on or when it wakes from sleep or standby the fan will ramp to 100% then either go off or run at a slow speed depending on the load and temp. and only ramp up under a full load or of the internal temp goes above about 50 deg C.

If this is how your PSU is working then I would say it is normal. if it is not working like this then please use the link on the left and request an RMA and let me know the case number so I can have this unit tested here in our LAB.

 

This is their intended design with this unit. RMAing it won't do any good since apparently the brand new one will do the same thing anyway.

 

...

Try one of the Seasonic OEM-Corsair improved units; they are beautiful for a noise-sensitive environment.

 

Wish i could. The mega store that i bought the PSU don't sell those. :S

 

I wish i had checked this site and saw that thread of the other user mentioning about this problem. The review sites said nothing about this issue. I didn't read all the comments on amazon or newegg but the ones i read were always like "works amazing, super silent, no sound" bla bla bla... The PSU is completely silent most of the times yes, and it's beautiful. But as soon as the fan becomes active, it becomes very distracting for a few seconds, which ruins the joy of having complete silence altogether.

 

Anyway. I've been doing some tests. Mounting the PSU with the fan facing upwards, to the interior of the case seemed to help the most. I'll share my insights in another thread when i'm done with it.

 

I had a major pc problem and i have been trying to fix it for days now. I got rid of that problem with this PSU but faced with this issue instead now. :(:

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OzgurHx is correct the fan profile/behavior is inherent in the design of the Flextronics based Corsair PSUs and RMAing will not fix a thing. I also did not read about the self-test in any reviews nor is it mentioned at the product webpage. Should come with a warning label on the box.

 

Maybe Corsair marketing should have only released the AX760 and AX860 PSUs before the Holiday deadline, and just let everyone know the digital AX760i and AX860i parts would become available in Q1 or Q2 with an improved fan profile, or different fan altogether. Then everyone could decide whether to purchase a non-digital now or wait for the CorsairLink bundled units.

 

Having a new H100i with CorsairLink I do miss the software than came with the AX860i, but I will never miss the noise, could not get that poorly thought out part out of my office quickly enough.

 

Maybe with a revision loyal Corsair fans can have both silence and software control, only time can tell us.

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Not going to make another thread. I kinda found a solution to this problem. If you are annoyed by this fan noise as well, this may help.

 

2 things helped together

 

1st:

http://s12.postimage.org/3plfy52nd/psu1.jpg

 

If i mount the PSU with it's fan facing downwards, it takes 10-15 mins for the fan to kick in and it keeps doing so continuously. Flip it the way i did, and intervals of that happening takes much more longer.

 

2nd:

http://s7.postimage.org/g4ip0ult3/fan1.jpg

 

I mount a 80x80x15 cpu heatsink fan as an exhaust fan. It pulls the air out of the PSU, doesn't blow into it. I did it that way to not interfere with the airflow of the actual fan when it's in action. It's 12v 0.45amps but i control it with my KAZE Q12. It runs at just %20 speed with no audible noise (the loudest thing in my case is my HDDs). If you are going to mount a fan like this, make sure to put a little distance between the fan and the unit (5mm was enough. I put some silicone to the screw holes and created 4 'bumps' on the corners of the fan and attached it that way with a wire as you can see) Else you won't be able to create airflow.

 

I ran 3d mark and Prime95 for 2 hours and the actual fan never started itself. PSU was slightly warm but it never got to that point (50C i believe?) for the actual fan to do its job. I don't see myself stressing the computer longer than that period anytime so i think i fixed this issue.

 

The ultimate fix to this problem would be changing the actual fan with something else with a lower max rpm but that would void the warranty. Since i got the unit a few days ago and it has a 7 year warranty with it, i just didn't want to risk it.

 

The fan 'solution' may not look pleasant but it works. I don't date with my case, i don't care about the looks :) To me, efficiency and silence are the most important factors.

 

Wish Corsair had implemented the fan the 'usual' way but, whatever. Problem is fixed. :headbang:

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Not going to make another thread. I kinda found a solution to this problem. If you are annoyed by this fan noise as well, this may help.

 

2 things helped together

 

1st:

http://s12.postimage.org/3plfy52nd/psu1.jpg

 

If i mount the PSU with it's fan facing downwards, it takes 10-15 mins for the fan to kick in and it keeps doing so continuously. Flip it the way i did, and intervals of that happening takes much more longer.

 

2nd:

http://s7.postimage.org/g4ip0ult3/fan1.jpg

 

I mount a 80x80x15 cpu heatsink fan as an exhaust fan. It pulls the air out of the PSU, doesn't blow into it. I did it that way to not interfere with the airflow of the actual fan when it's in action. It's 12v 0.45amps but i control it with my KAZE Q12. It runs at just %20 speed with no audible noise (the loudest thing in my case is my HDDs). If you are going to mount a fan like this, make sure to put a little distance between the fan and the unit (5mm was enough. I put some silicone to the screw holes and created 4 'bumps' on the corners of the fan and attached it that way with a wire as you can see) Else you won't be able to create airflow.

 

I ran 3d mark and Prime95 for 2 hours and the actual fan never started itself. PSU was slightly warm but it never got to that point (50C i believe?) for the actual fan to do its job. I don't see myself stressing the computer longer than that period anytime so i think i fixed this issue.

 

The ultimate fix to this problem would be changing the actual fan with something else with a lower max rpm but that would void the warranty. Since i got the unit a few days ago and it has a 7 year warranty with it, i just didn't want to risk it.

 

The fan 'solution' may not look pleasant but it works. I don't date with my case, i don't care about the looks :) To me, efficiency and silence are the most important factors.

 

Wish Corsair had implemented the fan the 'usual' way but, whatever. Problem is fixed. :headbang:

 

see post #40 ;)

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  • Corsair Employees

To be clear on a few thing mentioned in this Thread!

 

The Actual subcontractor we use is of little consequence, all of our PSUs are manufactured to our design and weather the item in question is made by Flextronics or Seasonic or whom ever we choose does not matter. There are a few models that are made by multiple contractors for us so that is not an accurate statement MatthewScores. I will pass on your statements but I would ask that you not speculate as it leads to miss information.

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  • 3 weeks later...

I've been an avid follower of Corsair products ever since my first computer build 5 years ago. I'm coming around to building my second PC this week and will be buying a 500R Case (my very first Corsair case) as well as Corsair memory (DOH) but sadly I will be passing Corsair PSU's this time around :(

 

Reason being is I have read over hundreds of threads on both computer enthusiast/review website forums and the occurring theme with Corsair PSU's is predominantly their noisy fans and coil whine. A lot of the forums I frequent are where enthusiasts share and spec new builds and these forums as with any come with support sections. I understand the vast majority of posts in such sections including this forum will be related to reports of faults/problems however it leaves me very little confidence buying a Corsair PSU or recommending one to my fellow enthusiasts when all I read is countless threads including this very forum where customers have had their noisy units RMA'd and received shiny new units only for them to inhibit the same problem. From a customers perspective, it makes me think this issue has been present since day 1 even before the manufacturing process, perhaps during R&D. Don't get me wrong, I'm not claiming all Corsair PSU's are defective but when I go to buy something, I expect it to be problem free and when I read of all the problems from people posting around the world on blogs, forums and even making youtube videos, it tends to put doubt in my mind.

 

My HX-520 which I installed in my first build in 2007 hasn't skipped a beat. Its fan remains spinning constantly albeit quiet. Before I built my very first PC, I had the experience of changing the PSU of an old base I used prior to my PC build and had the 'noob' experience we all have of going with the cheapy PSUs which end up with either a burnt down house or a big bang. Before I built my PC, I did research online and went with Corsair because of the top notch reviews people were giving your PSU's. Once I built my PC, I was so astonished with the quiet operation of my HX-520 and it's reliability, I recommended it to a few college friends who went and brought the same Corsair PSU's and I think both still continue to use them to this day.

 

I'm not sure what 'under the hood' changes have been made over the years but to me it seems like the issue is related to the temperature controlled fan and bearings on your PSU's. I can vouch for most people and honestly we don't care if the PSU fan is running 24/7 as long as it is quiet which your Seasonic models from the early days were. The fans on them started at low speed, and continued to run at low speed. I hope and pray that someone at Corsair is listening and that you guys go back to basics and focus on the quality of your PSU's and continue make top notch PSU's which we have all come to have known and loved. I hope one day in a future build I will again continue to use a Corsair PSU but unfortunately in my build this week, I don't have the confidence of going for another Corsair :(

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  • 4 weeks later...

Just got a replacement rma hx-850 psu gold, had a hx-850 80 plus silver,dont know why I wasn't sent a 850 80 plus silver?

 

I cant take It the fan ramping up and down :sigh!: thats only after using it for 5 hours.

 

what is a good psu that just stays quiet?

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  • Corsair Employees
What was your RMA number I would like to see that unit so we can test this? I have a unit at my desk and it almost quiet for me... I mean I hear the fan spin up but that is only because it is next to me on my desk in a system it would not be noticeable.
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Much like the original post I have exactly the experience with the HX750W which I received from an RMA about two days ago. Here's how it seems to go:

 

1. Turn on machine, works fine

2. Idle on my desktop, not doing anything strenuous

3. Fan sounds like to spins up to 100% for 3 seconds

4. Fan slows down and goes quiet again

5. Repeat steps 3-4 every so often (multiple times per hour).

 

I disabled all power saving features on my motherboard to check if it was in any way responsible for this method of operation (e.g. major changes in power draw which result in the fan spinning up) but there was no difference. During my brief testing, the HX650W didn't appear operate this way but was replaced for an unrelated issue (chirping).

 

Some other topics on the forum seem to imply that the HX750W is operating as intended but out of the three PSUs I have had from Corsair it is by far the loudest which can probably be attributed to the fan running at full speed before decreasing. The HX620W was near enough silent during operation and the HX650W fan performed more logically by gradually increasing and decreasing speed; had either reached full fan speed they would, most likely, have been equally loud.

 

Thing is I love the stability of Corsair PSUs and that has never been a problem. But it's the little things like this which are mounting up. In a mostly quiet room, hearing the fan spin up to full speed is immediately noticeable. Would be interesting to hear some thoughts on this and whether the behaviour really is intended or unusual. This post seems to imply it was a design issue which was fixed:

 

http://forum.corsair.com/forums/showpost.php?p=612453&postcount=15

 

Is a third RMA going to result in exactly the same problem?

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I feel your pain OzgurHX. I had a new AX860i (Flextronics) that would spin its fan every 12seconds when it reached 42C up to 800rpm loud for just 1 or 2seconds then back down again for no apparent reason. Also the fan would run the self-test to maximum rpm at boot and out of sleep mode, sounded like a Harrier Jet Fighter taking off. I think all the Flextronics-OEM based Corsair PSUs do this self-test thing. Sent mine back to Amazon and got a plain AX860 (Seasonic) without the i. Its Seasonic based and the fan never spins at all, perfectly silent, brilliant power supply. The fan will spin up if you want it too, by placing in Normal fan mode via a toggle switch on the unit, but even then it runs so slow, cannot be heard. The AX860 Platinum is pure love.:hihi:

 

Try one of the Seasonic OEM-Corsair improved units; they are beautiful for a noise-sensitive environment.

 

I 2nd to that just returned mine too.

Its not a temperature issue to spin up with no obvious reason at 100-W usage 35oC while idling in desktop.

Its obviously a failed series controller unit on lots if not all flextronics units.My guess is that in the last weeks development an assortment skipped the Quality Control check maybe due to adding fan-fan controller after the rest of the psu was tested and found OK.

Its a profound problem that im sure if all flextronics based PSU had the returns would be massive.The psu spins so loud i had mine tested with manual through Corsair link and the equivalent noise was 1500+ rpm.That's definetely audible and annoying even in a 1200+ rpm full fan air cooled desktop PC.

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