How to lower my fan speed without relying on my broken temp sensor showing 127c...

Toggle sidebar Toggle sidebar
T

Tim Still

Reputable
May 5, 2015
29
0
4,530
Ok, so my temp sensor reads 127c on multiple applications.. bios,speedfan,ai suite. and i have felt my heat sink and it is not hot. The man thing for me right now is the Fan is blowing at 5500RPM CONSTANTLY.

Is there a way i can control the rpm manually without relying on the temp sensor to adjust itself?


xd74a1.jpg
 
Solution
clutchc
Remove the cooler from the PC and take off the fan. Then take it outside and use compressed air to blow out the heat sink. You may not have to remove the fan, but hold it stationary rather than let it spin as you blow out the heat sink.
Then clean off the old (probably dried out) thermal paste from the cooler and the CPU and replace with new.
Sort by date Sort by votes
clutchc

clutchc

Titan
Ambassador
Apr 22, 2009
43,150
411
131,790
Maybe the heat sink is not hot because it isn't having the CPU heat transferred to it correctly. dried out or poorly applied TIM. Poor contact between heat sink and CPU.
Although, the CPU should shut down before it reaches 127C. So the above may not be the case.
Can you set the fan speed manually in BIOS? What motherboard? Stock cooler?
 
Upvote 0 Downvote
P

Paperdoc

Polypheme
Ambassador
Oct 19, 2006
11,278
1,031
69,340
I agree it's hard to believe the CPU temp is running at 127C. But what if it is?!

Now, clutchc has a good point. If heat is not flowing well from CPU to heatsink, that would explain both the high CPU temps and the cool heatsink. If your temp sensor is NOT broken and is telling you the truth, you have a REAL problem! I see that the temp recorder graph shows brief periods when the CPU temp drops down to 55C then rises again. Maybe that is happening because the mobo is throttling the CPU to a much slower speed to prevent it from destroying itself.

Review what was done in assembling the system. In particular, how was the thermal paste applied? Many heatsinks arrive with the thermal paste already applied and protected with a plastic film. You MUST remove the film before attaching the heatsink to the CPU top. Was that done?

If you had to apply your own thermal paste, did you follow the maker's instructions? Too much paste is almost as bad as too little. For example, on my system the amount of paste required was "about the size of one grain of rice". Others are different, depending on CPU type and size. Then there are suggestions about how to get that paste to spread around just right so that the entire contact area between CPU top and heatsink bottom is covered with a thin film of paste.

By the way, the CPU temperature sensor is built into the CPU chip itself. It is part of the circuitry printed on the CPU substrate. So it is rare that this sensor is "broken". However, I suppose a poor connection from the appropriate CPU pin to the socket might give bad readings.
 
Upvote 0 Downvote
clutchc

clutchc

Titan
Ambassador
Apr 22, 2009
43,150
411
131,790
Paperdoc has a good point. I didn't catch that graph indication. That indeed looks like it's throttling. Is this an Intel CPU w/push pin cooler mountings? If so, check that one of the push pins is not loose or popped out of the hole. One by one... release them, reset them, and press them back into the hole until they click. Then (if possible) look behind the MB and be sure the fingers have spread themselves open behind the board properly.
 
Upvote 0 Downvote
T

Tim Still

Reputable
May 5, 2015
29
0
4,530
I am running a M5A88-v Evo MOBO

CPU:

rjmiix.jpg



127c is absurd and is also the highest temp that sensors indicate. i read that if a sensor is broken it either shows 0c or 127c. and it does not fluctuate besides going down to as you both mentioned 55c.
 
Upvote 0 Downvote
P

Paperdoc

Polypheme
Ambassador
Oct 19, 2006
11,278
1,031
69,340
I'm not clear what you mean by "that...". If you are questioning whether the stock cooler is just not good enough, it should not be a problem. Especially, a stock cooler will NOT be so bad as to act like it is doing nothing.

Since it is a stock cooler, you DID remove the plastic film on its pasted face before installing?
 
Upvote 0 Downvote
clutchc

clutchc

Titan
Ambassador
Apr 22, 2009
43,150
411
131,790
What is that white stuff under the fan blades in the pic? If that is dust, dirt, or other foreign matter blocking air flow to the heat sink... absolutely that is the matter!
Btw, that is not an Intel CPU. So ignore the part about checking the push pins. AMD coolers just clip on.
 
Upvote 0 Downvote
T

Tim Still

Reputable
May 5, 2015
29
0
4,530
YES it was dust! caked up. i confirmed with the previous owner (my brother) who built it that the temp sensor is messed up. i tried to clean all the dust out of that.. not very well, but it is a lot cleaner.

No worries beside the Throttling thing.. When you guys said this i notice how my fan will speed up fast and then go idle then throttle back up again... but it only does this probably 7/10 startups
 
Upvote 0 Downvote
clutchc

clutchc

Titan
Ambassador
Apr 22, 2009
43,150
411
131,790
Remove the cooler from the PC and take off the fan. Then take it outside and use compressed air to blow out the heat sink. You may not have to remove the fan, but hold it stationary rather than let it spin as you blow out the heat sink.
Then clean off the old (probably dried out) thermal paste from the cooler and the CPU and replace with new.
 
Upvote 0 Downvote
Solution
P

Paperdoc

Polypheme
Ambassador
Oct 19, 2006
11,278
1,031
69,340
Good eyes, clutchc!

OP, the fan speed changes you describe on start-up are normal.

What usually happens (with a properly working system) is this:
1. On start-up, the fan automatic control system sends the fan the full 12 VDC to ensure it starts up properly.
2. After most of the POST process is finished (less than 30 sec, maybe only 5 to 10) the automatic control system gets a valid reading from the CPU temp sensor, which is cool - the unit has been off. So the fan speed slows down to match the measured CPU temp.
3. As you use the system and the CPU heats up, the fan speed rises and then changes up and down as the CPU load changes.

MAYBE your brother was wrong. If he did not realize how badly the heatsink was clogged, just as you did not, he may have come to the wrong conclusion, too. See how it all works when you get it cleaned, fitted with new thermal paste and reassembled properly.
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom