CPU fan stopping and starting

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Heard some strange noises from inside my PC. I took off the case and the CPU fan is constantly stopping and starting! I have absolutely no idea what this could be. Its a stock Core2 6300, stock heatsink on a DS3. Anyone know what this could be? Knackered fan?
 
It seems to be fine now. Something to do with a cold boot? Can't say I've ever experienced this before.
 
Ah right. Never seen it before. Maybe due to the fact it's so cold in here.

While I am here, mind checking my PSU rails? I've had a couple of spontaneous PC power off's recently. I have no understating of rails but the +12v looks suspicious compared to the rest?

2110712194_2820e837b2_o.png
 
Stopping and starting? How erratically? If it's literally completely stopping, and then coming on again - I'm not sure that's normal?

At least, in my personal experience, fans which automatically adjust given the core temperatures will gradually increase/decrease their RPM as the temperatures changes.
However, perhaps there are some which are meant behave in the way you have mentioned. I'm sure someone can verify this.

Since you mention random power offs, I'd certainly be concerned about your PSU. It may be causing the CPU fan problem (if indeed it is problem). I don't know much about rails etc, so I can't comment, however from what you've described you may have a PSU issue.

What model is the PSU?
 
Corsair 520W. I have a video of the fan but I'm trying to find some web space to upload it at the moment. The CPU fan hasn't stopped once since I started the thread though. As for the power offs, there is only one I know for sure about. The rest of the time I come to the computer in the morning and its switched off. There's nothing in event viewer about user-controlled shut-downs during the night, unless it doesn't log those things or someone is turning it off by pushing in thee power button.
 
The stock HSF fan shouldn't stop all together, it's not that good a HSF that it can afford to do this. Check the connection of the fan with the mobo, pull it off and plug it back in to see if things get better.
 
I have established that no one has been switching off the PC at night. It's powering down itself. Just checking my temps now and the CPU is idling around 50C and when I posted this morning it was the low 40s. The Pc has been on all day.

Here is a video of the CPU fan behaviour:

http://www.bluesuncorp.co.uk/moar/DSCF2159.AVI
 
And here is an updated speedfan grab. The rails seem to have changed since this morning. Should I be worried about those stats?

2111374056_4cc223c996_o.png
 
Fan shouldn't be doing that, i know when mine was set to the temperature of the cpu, on first swith on it would twich until the CPU got to the right temperature for it to come on, then it used to spin all the time, but somethings wrong there by the looks if it to me, shouldn't be stopping/starting all the time like that.
 
It never used to do that. It always stalled for a second on boot but that's for the reasons you gave. It hasn't done it since today though. I'm damn tempted to just order an AC Freezer 7 Pro. Should I?
 
Woke up again this morning to find the machine has once again powered down by itself overnight and the CPU fan has commenced its stop\start routine again. I am really stumped. I have absolutely no clue what could be causing the power downs and the problem with the fan. Only thing I really know for sure is that the fan only plays up on cold boots. Anyone want to take a shot at it again?
 
There are some fans/mobo combos that will completely turn the fan off for a period of time, then kick in when temperatures start to rise...Had this it work once while upgrading bios' in dos etc.

**EDIT**

the CPU is idling around 50C
See now, to me, that's reasonably hot for an idle state =/

Have you tried removing the heatsink, and seeing if the thermal compound has been utilised etc? ie not in it's original state and melted onto the cpu surface...
 
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I don't suppose you would know if it is normal behaviour for a DS3? Its never done anything like this since March when the machine was built. Cold temperatures due to the time of year? The fan is now acting normal again.
 
Is there any fan setting's in the bios? Might be worth taking a look.

What board do you actually have?
 
My friends coolermaster heatsink fan did this on his DS4 board on a cold boot. Nothing to worry about imo.
 
Could literally be a cold boot issue.

You could try changing the fan setting's, so they aren't on auto or something etc. Looking at the manual there are a few combinations you could try.

Or you could just leave it / stick a heater infront of your pc for ten mins before you turn it on every time throughout the winter :rolleyes:
 
It must be a cold boot thing. Couldn't find a lot in the BIOS about the fan specific to this issue. It's just set to Auto and I didn't understand the other options e.g. Legacy. I'm not too worried about it as the fan is 100% perfect once the PC has warmed up.
What does worry me is the fact it seems to be turning itself off at night. A real mystery. Can computers do strange things like that if the temperature is too cold? :/
 
Are you running Vista? You might need to change the power settings as it could be set to turn itself off after a certain amount of time idle.
 
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