BleepingComputer.com: Athlon CPU getting very hot

I am helping my dad with his computer and have just discovered, that the cpu gets really hot when under load.
The pc is a HP Pavilion a6330.sc Desktop PC and cpu is an AMD Athlon 64 X2 5000+ (Brisbane G2).
The cpu fan/heatsink is stock and the label on the fan reads "AVC F7311NC".
In Prime95 stress test the cpu temps get up to nearly 70c° within 15 minutes, before i stop the test for precaution. I read that the max temp for this cpu model is 55-68c°.
These temps are reported the same by HWMonitor and Core Temp. Idle temps are about 30c° for core #0 and 22c° for core #1.
The really weird thing is, that the cpu fan speed does not adjust when temperature increases.
The speed is fixed at about 1800rpm no matter what the cpu load or temp is at. These fan RPMs are reported by HWMonitor and seems correct, as i cannot hear or see the fan increase in speed. I have tried to connect the cpu fan to sys power connecter, but the speed stays at about 1800rpm.
This just makes no sense to me, as i would think the cpu fan is supposed to be temperature adjusted by the motherboard, and not running at a fixed speed that results in the cpu overheating. Any input is appreciated.

probably already looked at this, but if its an older pc try using canned air and blowing out the cpu fan and heatsink of dust...that may be ure only problem ...my old pc i had to do that with and it decreased temps under load by like 10-15C (it was full of dust)

another thing u could try is to get an aftermarket cpu cooler

http://www.newegg.com/Product/Product.aspx?Item=N82E16835200014


that one is just a cheap solution but it may be all u need

Depending on how old the PC is. Not only a cleaning as mentioned but also removing the heat sink, cleaning the old thermal paste and replacing it with a quality paste can go a long way as well.

I have dusted off the insides with compressed air several times before, so there is no significant dust build up.
The motherboard is mounted upside down in this case and the PSU is at the top. A 100 or 120mm fan is mounted behind the cpu heatsink in the bottom of the case and is spinning at just below 1000rpm.

I think i will try and reapply the thermal paste as suggested.
If i buy a new cooler for the cpu, do you think it will still run at a fixed speed as now, or would it be able to be temperature adjusted? Could the HP bios be set up to supply a constant 12v to the cpu fan?

i know that some coolers come with a fan speed adjustment but if not u may be able to use speedfan to change the temps

btw what is ure whole cooling for ure case not just the cpu...like is there good overall cooling...u may only need to put more fans in the case if u can

I will be in the minority and say,"Don't worry about it."

Per AMD, the max temp on that should be 72C. Now, 70C is close to max temp, but how often do you run PRIME95 when you aren't purposely testing your cooling (answer is "never"). Monitor temps during normal stresses and see what happens. Is your dad an avid gamer? What programs does he use that stresses both cores at 100%?

If that CPU is bumping 70C during normal operation, then worry. If the only time it gets near 70C is when purposely stress testing it, relax.

Is the BIOS set to control fan speed? Usually if BIOS control of fan speed is deactivated, fan speed defaults to "max". 1800 RPM might be the max speed for that fan. Not unusual in OEMs in order to keep noise/customer complaints down.

I have just discovered something new and really mysterious.

I notice that the stock cpu fan have developed a rather irritating humming noise.
So i thought about replacing it with a new one and i had som unused case fans lying, but when i plug a 80mm fan rated at 2000rpm into the cpu fan header, it only rotates at around 550rpm.
Another 80mm fan rated at 2500rpm rotates around 600rpm and a 92mm fan rated at 2000rpm only spins at 770rpm.

The same applies to the chassis fan header and all of the above fans do not increase in speed with cpu temps, just like the stock fan is not doing.
I am really baffled about this new discovery.

This have to mean that there is only supplied a constant 5v or so, at both the cpu and chassis fan headers.
What do i do about this? I cannot even install a new fan or complete heatsink for that matter, as the fans will spin much to slow and there is no way to adjust it in the bios.

i would try http://www.almico.com/speedfan.php speedfan to try and control their speeds

SpeedFan does the trick, yesterday i increased my cpu fan from 1650 to 3370 rpm. But the program must be running and i'm not exactly sure how to make that speed stay at the speed.

Speedfan does not work for me, it won't even start and just stops responding.
I quess it is not compatible with this motherboard chipset.

I have reconfirmed that the fan speeds are correct.
I shut the PC off and also turned power to it off. Then i installed the new 80mm fan, that runs 1800rpm at 12v in my own computer, then powered on the PC again and HWMonitor shows the speed to be 570rpm, which corresponds to the fan speed i observe from it.

It just seems stupid to me, that HP have chosen such a setup.
The cpu fan are not temperature controlled in any way. It uses a custom fan that runs fixed on 1800rpm at only 5v or less, supplied from the cpu fan header. The fan or voltage supplied cannot be adjusted in bios, so there is no way of using a standard fan, connected to the cpu header.
The only way to change the old fan, is to connect a standard 80mm fan directly to the 12v power from the psu, via an adapter.

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That's what i did when i ran out cpu fan plug.

One thing I like doing, and since you have covered all the standard things. Cleaning heat sink and fan\ replacing thermal paste.

When ever I want extra cooling and do not have a lot of $$ to spend. I get on of these > EXAMPLE ONLY. Top it off with a quality 120mm fan.

This does a number of things. 1) It lifts the fan off of the heat sink eliminating the dead air spot that the fan hub creates. 2) Moves more air. 3) Larger fans spinning slower but moving as much\more air then a smaller fan spinning faster are usually quieter.

This method has dropped CPU temps on every PC I have done it to by several degrees C.

An alternative to SpeedFan, Core Temp - http://www.alcpu.com/CoreTemp/ .

Louis