file:  G:\G_MyDoc\PC\PC_fan_buzzing_noise.htm

http://www.tomshardware.com/forum/293876-28-computer-creates-irritating-buzzing-sound-random-intervals 

Since the last two weeks, there is a weird buzzing sound [like that of a bee] emanating from inside the system at random intervals. It lasts for 4-5 seconds, and then stops only to occur again. Initially, I ignored it. But when it continued this way, I opened up the CPU while the system was running. 

Now, there are two fans inside my CPU: a big one mounted vertically at the back [kind of like an exhaust fan] and a smaller one screwed horizontally on a heat sink [processor fan I suppose?]. I discovered that the sound was emanating from the processor fan. How did I know? Well, I waited for the buzzing sound to occur again and when it did, I placed a finger on the center of the fan. The fan stopped rotating and so did the buzzing sound. 

The fan is screwed on to the heat sink. Initially, I thought that it might be rubbing against a rough surface. So I unscrewed it and took a peek underneath. But it seemed fine to me. Then, I cleaned the fan with a hair dryer. It didn’t have much of dust anyway as it’s just 2 months old. I also used the hair dryer to clean the top of the heat sink, then screwed the fan back on, and started the system. It was fine for a couple of minutes and then the buzzing sound materialized once again! And this continues to occur at random intervals even now. 

I have experienced “noisy” computers before and I do understand that it’s normal for computers to be slightly noisy due to the cooling fans. However, this buzzing sound is something new to me. Can anyone diagnose this problem and help me get rid of the buzzing sound. It gets on my nerves, especially at nights while I am surfing. 

My system configuration is as below: 

AMD Athlon II X3 440 Processor on MSI 880GMA-E45 motherboard with 2GB Corsair DDR3 RAM 

OS is Windows 7 Ultimate Ed. 32bit. 

By the way, I had already enabled the "AMD Cool n Quiet" feature in my BIOS setup a long time ago.

Response 1 (11-17-2010 at 08:02:44 PM):

If you are using cool n quiet is the sound occurring as the heat increases and the fan speeds up? 

Could be the fan has developed a fault, noisy bearings which would possibly need replacing as will only get worse. 

If it needs replacing and you are using a stock AMD cooler you could replace with a better silent cooler? 

Try plugging the fan directly into a socket without cool n quiet so it runs full speed. 

If it makes the noise you know that's your problem. 

Also when it makes the noise tap the centre of the fan while its spinning to see if you can get it to stop. 

Again another sign that the fans had it. 

Well honestly, I wouldn't know just when the heat increases and the fan speeds up. To me, it always seems to run at the same speed. Is there a way to know or measure these things? 

I don't have another system right now. I disabled AMD's "Cool n Quiet" feature in my BIOS setup a few minutes back. But this did not stop the buzzing sound. Just what is the purpose of Cool n Quiet? 

Regarding noisy fan bearings, this is a brand new system anyway. So shouldn't the fan be running smoothly? I do remember that the heat sink and fan were part of the AMD processor package/kit.

Hi 
I agree with the chief : 
1. dismantle and disassemble the fan and lubricate the bearing. 
or 
2. Replace the fan 
or 
3. Use the oppotunity to replace the entire CPU cooler, specially if you're presently only using the stock cooler. 
Considering your CPU the COOLER MASTER Hyper 212 Plus would indeed be an excellent choice for a new good-value cooler.