Unknown buzzing / high pitched sound coming from PC

I'm kind of embarrassed to ask a question before I've been able to contribute much to the community, but here goes:

In August I built my first computer, specs:

Intel E6750
Gigabyte GA-P35-DS3L
2 x 1GB Crucial Ballistix DDR2 800
BFG 7900GS OC
Western Digital WD5000AAKS SATA 3.0 + old PATA Maxtor
Antec Earthwatts 500
BenQ DVD-RW PATA

Everything had worked perfectly since the day I built it, and recently I've been trying to sell it since college is going to be starting up again. Unfortunately, a couple of days ago the computer has started making a strange, high pitched buzzing noise (I'm glad that the guy who was going to buy it today couldn't make it).

I've done some tests to try to narrow the problems down.

• Does not buzz in BIOS.
• Buzzes in Windows and Linux
• Does not buzz during memtest, memtest shows no errors after 2 passes
• Buzzing still occurs when both hard drives and the dvd-rw drive are disconnected.
• Taking side off case of and stretching out the PSU cables that were previously crammed under the dvd-rw did not stop buzzing.
• Buzzes when booted from linux on flash drive with other drives removed.
• Raising / Lowering video card fan speed does not affect buzzing.

And perhaps the greatest clue?

• Stops buzzing when opening programs / under load (ie. Prime95).

I don't think it could be any of the fans, since the buzzing stops under load, curiously enough.

I'm dreading that something's wrong with my mobo or psu, but if I've missed something painfully obvious, please suggest.

If anyone has any ideas for the cause or remedy, or perhaps any more tests, I'll be very thankful. I tried searching the forum/google, but didn't find much. Thanks!

Could be the CPU fan surely? If it goes away under load then the CPU fan would be speeding up, therefore it may stop the buzzing?

Jaffa Cakes! said:

Could be the CPU fan surely? If it goes away under load then the CPU fan would be speeding up, therefore it may stop the buzzing?

Click to expand...

I'm going to try disabling the auto fan speed in the BIOS so it only runs full speed, I'll report back in a minute.

Jaffa Cakes! said:

Could be the CPU fan surely? If it goes away under load then the CPU fan would be speeding up, therefore it may stop the buzzing?

Click to expand...

Nope, with fan constantly at full speed (using stock cooler), buzzing persists. Once I fire up Prime95, buzzing instantly stops until I stop Prime95, at which it resumes buzzing. It also would not quite explain why there is no buzzing in BIOS. Buzzing seems to be coming from lower half of the case (PSU is bottom mounted), but I'm not completely certain.

Open the case and find where the buzzing is coming from with your ears.
You should be able to narrow it down a bit more for us.
ie if you remove the PSU from the case, is the sound coming from the PC still

Nenu said:

Open the case and find where the buzzing is coming from with your ears.
You should be able to narrow it down a bit more for us.
ie if you remove the PSU from the case, is the sound coming from the PC still

Click to expand...

My fears confirmed: I pulled out my PSU as far as possible, and I'm 90% sure that the problem lies within it. I'm not particularly thrilled about voiding my warranty when I probably won't be able to fix anything inside anyway. Game over? Does a buzzying PSU necessarily mean near and unavoidable death? Is there anyway that the buzzing is being caused by something external?

The PSU is probably the worst part to go bad for me, since the ATX connector is really tightly connected. I've tried to pull it out a couple of times before, but stopped because I was afraid that I'd snap my mobo.

(sorry, that was a lot of questions)

It depends what is buzzing.

Could it be the fan catching something?

If not and it sounds like mains hum then most likely it is the transformer and will be ok if you can cope with the noise.
It is possible a mains type hum could come from other components though but it is most likely to be the transformer.
Still a risk.

Any other type of buzzing I would not be using the PSU unless it has been looked at by a pro.

ps to remove the stuck connector, push down on the motherboard around the connector with one hand and grab the connector and its clip very hard with the other hand while also getting a tight grip on the wire.
Pull hard as nuts!
Make sure there are no drives etc to catch your hand on as it flies upwards.

Nenu said:

It depends what is buzzing.

Could it be the fan catching something?

If not and it sounds like mains hum then most likely it is the transformer and will be ok if you can cope with the noise.
It is possible a mains type hum could come from other components though but it is most likely to be the transformer.
Still a risk.

Any other type of buzzing I would not be using the PSU unless it has been looked at by a pro.

ps to remove the stuck connector, push down on the motherboard around the connector with one hand and grab the connector and its clip very hard with the other hand while also getting a tight grip on the wire.
Pull hard as nuts!
Make sure there are no drives etc to catch your hand on as it flies upwards.

Click to expand...

The PSU only has one small fan in the back, and it doesn't seem to be touching anything. I tried unplugging all drives and fans, also to no avail. I listened to the samples of a mains hum on Wikipedia, and the sound I'm hearing is totally different, it's very high and irritating.

I'll try your advice for pulling out the connector. I'm mainly worried because I'm missing one of the mobo standoffs closest to the connector (I'd originally screwed the standoff in too far, and it wouldn't hold so I removed it).

Thanks for all the help!

It will be a coil or a transformer that is making the high pitched sound.

I have the same noise. It seems to happen when the CPU/Memory is crunching numbers. I am not sure if it is possible to be the Memory Hub Controller.

It is extremely annoying and may make me ditch this computer.

I have disconnected the fans, CD/DVD, tried different hard drives, swapped out the PSU, tried different ram and different CPU. With no solution.

I tried turning off the onboard network, removing the wireless mouse, thied using onboard and PCI-E video cards, and covered up the onboard speaker.

No fix yet

Intel Q35 chipset.

I believe I've seen reports of this being linked to the front panel audio connector on that motherboard. Disconnect that and see if it still buzzes.

When i first put together my computer I had forgotten to plug my 8800 GT into the PSU. When I booted up the PC it started making a high pitch screech. I plugged the PSU cord into the GT and when I turned on the computer the screeching stopped.

Not sure if this is the same problem but I thought I would add it in case you overlooked that too. I had never had to plug a GPU into the PSU before.

I ended up using a power supply from a Dell Precision 390 and noise was gone. The Power Supply from my Dell Optiplex 755 was causing a Voltage drop and the noise was a result. The 390's P.S. supplies a more reliable-continous power. Just a follow up for others maybe having the problem.