Well, that's what I thought originally. Every so often, something with a motor makes a quite loud whiring noise, which disappears after a few minutes, and I immediately thought it was the hard drive starting to give up the ghost. However, a mate at work suggested I download a little freeware program called "Speedfan". This would allow me to monitor the temperature of the HDD among other things. I've got this installed now and, low and behold it's not the HDD.

Fan No1 is the CPU fan and this runs at a constant 1500 rpm, give or take 7 rpm.

Fan No2 ( don't know what this cools) but it runs at 2733 rpm, but when the noise starts, it drops to about 2100 rpm. As the noise goes away, the fan speeds back up to 2733 rpm.

Now I don't know whether this drop in rpm is the cause or the effect, but either way, it's annoying.

All temperatures run at a constant 30 degrees except the core temp which is 22, so it looks to my untrained eye everything is OK

Any suggestions out there?

TIA,

Cheers, Trev.

Try a drop of oil if there is access to the shaft.

Hi Trev, this doesn't sound too much of a problem but can be a worry if you don't know what it is. Your diagnosis sounds pretty good. However, in my experience it is the cpu fan that mostly makes this noise as it's the one that get the hottest, often wearing the most, and of course like the others, attracts dust. Depending on what processor you are running your cpu fan speed looks a bit low at 1500rpm. If I might suggest, this my actually be the case fan rather than the cpu. So, it may actually be the cpu fan that is noisey. Sometime these software thingies reverse the case and cpu fans. But I could be wrong of course. New fans are easy to source and fit. But if it's the cpu fan, make sure to get the exact one for your cpu to avoid overheating. Good luck.

I partially agree with the above, it is more likely the variable speed fan is the cpu unit, as it will speed up and slow down to match the heat being produced by the cpu under load (if so enabled).

However it is possible to get a cpu fan with rpm speeds that low, my Vanquisher heatsink fan runs at a MAXIMUM of 1500rpm for instance, and my previous fan (on a Zalman heatsink), used to run between 800-1200rpm..

Theres alot of variables here...

What motherboard you running

What CPU you running

What case you running

etc etc

In my computer-geek experience (and off what youve said) it will be the case fan - these are made to a low-cost. so its common for the bearings to fail.

The ultimate test would be this: take the side off your machine.. you should be able to see the CPU fan, and also the case fan. when the noise occurs, stop the case fan with your finger/object and see if the noise stops.

if not.. try the same with the CPU fan - note some motherboards with auto-shutdown if the CPU fan is stopped. but dont worry you wont cause any damage.

New fans are a couple of quid from http://scan.co.uk - only need to know what size they are.

ah yes the finger test

Just dab the centre, otherwise you'll nip your finger

HTH

Another question- have you got any cooling on the HDD . Again the fans on HDD coolers( or the ones I've had anyway) are of similar quality to the case fans.

Thank you all for your input. Did the "finger test" and it was indeed the case fan on the back of the machine. It was a brushless motor and the fan was wobbling about a bit. Just been down to Maplins and got myself a Zalman Ultra Quiet Fan and the difference is quite marked. Thanks again for your help.

Cheers, Trev.

Splendid! Happy cooling....

Thank you all for your input. Did the "finger test" and it was indeed the case fan on the back of the machine. It was a brushless motor and the fan was wobbling about a bit. Just been down to Maplins and got myself a Zalman Ultra Quiet Fan and the difference is quite marked. Thanks again for your help.

Cheers, Trev.

I've found that taking the sticker off and applying WD40, then a pad with coking oil makes the fans last a bit longer. ( Tight Git tip).

I've found that taking the sticker off and applying WD40, then a pad with coking oil makes the fans last a bit longer. ( Tight Git tip).

Get yourself on SuperScrimpers