# Erratic power supply fan.



## cole.p (Jun 17, 2011)

Hello, I'd like to thank you in advance for checking out my thread.

I started up my computer this afternoon and noticed that my power supply's fan was running a lot louder and faster than normal. I dismissed this as a fluke as the computer started up.

I booted normally into Windows 7 (SP1) and let my computer idle on the desktop for a few minutes. I noticed the fan revving up and slowing down erratically while idling which concerned me. I opened up SpeedFan and took a reading of the fan over the course of a few minutes. Keep in mind that these values were taken during *idling*.










As you can see, the fan's speed jumps up and down erratically, with no known cause.

If I enter the PC Health section of my boot menu, I see the following:

*CPU Temp (PECI Mode):* 67
*System Temp:* 34C/93F
*CPU Fan Speed:* 4411-4440 RPM
*System Fan Speed: *N/A
*CPU Core:* 1.216V
*+1.1V: *1.120
*+3.30V: *3.408
*+5.00V: *4.999 - 5.026
*+12.0V: *11.904 - 11.968
*5VSB: *4.972V
*VBAT: *3.216
*Smart Fan:* Enabled

For the properties with multiple values, note that the two values alternate back and forth. For instance, when the Fan is 4411 RPM, the +5/+12 are the lower number, and when the Fan is 4400 those values are the higher of the two.

My computer's specs are as follows:

Core 2 Quad Q8300 @ 2.5GHz
6 GB DDR3
Radeon HD 5770

I'm not sure of the brand/wattage of the power supply, but it has been running this setup for several months now without a problem. The computer is an Acer M5800 desktop.

If you need any additional information, please let me know!

Thank you.


----------



## hhnq04 (Mar 19, 2008)

Have you given the insides a good cleaning? Sometimes dust buildup on components raises temps which could cause the fan to turn on to cool things down, and then turn off once they are cool. Doesn't _exactly _explain the spikes, but it could help eliminate them.

:EDIT:
So after I clicked post, I remembered this was about the power supply fan, and not case / gpu / cpu fans...good morning! I'd still give it a good cleaning / dusting if it looks like it needs it.


----------



## cole.p (Jun 17, 2011)

That was my first inclination. So I cleaned out the power supply fan and gave the rest of my case and components a good cleaning. Still experiencing the problem. The temperature isn't fluctuating like the fan speed is.


----------



## greenbrucelee (Apr 24, 2007)

look at the label on the psu and post what it says (it should tell you the brand and wattage).

Second do not trust speedfan for anything apart from fan speed. Use the BIOS for temps and voltages. If your bios is locked download CPUID hardware monitor and post the voltages and temps from that.


----------



## cole.p (Jun 17, 2011)

I should mention that those figures are from the Bios menu not from Speedfan. The only thing I used Speedfan for was to display the erratic behavior of the fan speed during idling.


----------



## cole.p (Jun 17, 2011)

I apologize for the second post.

I just got home and checked my power supply. It is a FSP450-60EP, manufactured by FSP Group, Inc. 450 Max Wattage, 500 Peak Wattage.


----------



## greenbrucelee (Apr 24, 2007)

FSP power supplies are known for failure as they are a dodgy brand howveer your voltages look ok but since its FSP I wouldn't trust it to power my pc.


----------



## cole.p (Jun 17, 2011)

At this point I'm just going to buy a new Power Supply. They're not that expensive and I'd rather not risk the rest of my PC.


----------



## greenbrucelee (Apr 24, 2007)

make sure you buy a good brand such as corsair, xfx or seasonic and you should get a minimum of 550w. Buying a generic brand is never a good idea and will cause you more problems.


----------



## Tyree (May 10, 2009)

cole.p said:


> At this point I'm just going to buy a new Power Supply. They're not that expensive and I'd rather not risk the rest of my PC.


Good choice. Follow the suggestions provided by greenbrucelee and you'll be good.


----------



## cole.p (Jun 17, 2011)

Well...I replaced the power supply with a Corsair GS700 (700 Watt). I know 700 Watt is a bit overboard but whatever. 

I booted up my rig and I'm still having the same problem. I really don't know what to do at this point...

What component tells the fan how fast to spin? Is it reading temperatures from the motherboard? I'm not really _too_ well-versed computers, but I know enough to do replacements like this and whatnot.


----------



## greenbrucelee (Apr 24, 2007)

there are sensors on the motherboard but when it comes to psus its sensors in the psu and you shouldn't tamper with a psu unless your a qualified electrical engineer. A psu can carry a lethal charge weeks after it has been switched off.

Are you sure its the psu fan that is revving and not the cpu fan? if cpu fan rteplace thermal paste

Check mobo for signs of damage like burn marks or leaking capacitors FSP power supplies are known to do this.


----------



## IrineTAntec (Jun 22, 2011)

this is an example that the problem should be first objectively observed to work out a solution. Corsair PSU is not a panacea.


----------

