Rear Case Fan Slowing down midway

[JamesClark]

Hello guys I'm new here because i need some help. Is it natural for the case fan to start spinning fast then slows down midway?. I noticed this when I tried to remove some dust in it then tried to run it again after and I noticed that the fan was spinning fast then after some hours the fan started spinning slowly, I tried to search for some topics related to it and found that I need to replace it or put some lubrication but I don't know what to do since I just bought this pc build for like 8 months ago and because of it my pc is heating up. thank you very much for anyone who answer.

[BetteBalterZen]

1 hour ago, JamesClark said:

Hello guys I'm new here because i need some help. Is it natural for the case fan to start spinning fast then slows down midway?. I noticed this when I tried to remove some dust in it then tried to run it again after and I noticed that the fan was spinning fast then after some hours the fan started spinning slowly, I tried to search for some topics related to it and found that I need to replace it or put some lubrication but I don't know what to do since I just bought this pc build for like 8 months ago and because of it my pc is heating up. thank you very much for anyone who answer.

Too aggressive fan curve maybe? Slight load on the CPU / slightly higher temps, and fans go fast. 

If I were you, I'd check temps with fx HWiNFO and see if the temps are good or not. If they're good, most likely just an aggressive fan curve, which could easily be tweaked. 

[JamesClark]

On 5/11/2021 at 12:51 AM, BetteBalterZen said:

Too aggressive fan curve maybe? Slight load on the CPU / slightly higher temps, and fans go fast. 

If I were you, I'd check temps with fx HWiNFO and see if the temps are good or not. If they're good, most likely just an aggressive fan curve, which could easily be tweaked. 

Hello Sir, thank you for answering, I tried to do what you said and checked my Temps. My temps stands between 40-50C is it good? is that the normal temp?

[BetteBalterZen]

4 hours ago, JamesClark said:

Hello Sir, thank you for answering, I tried to do what you said and checked my Temps. My temps stands between 40-50C is it good? is that the normal temp?

If you have alright cooling, I'd say idle temps in the 40s to 50s with an Intel CPU, is a tat high. With AMD, and please correct me if I'm wrong, it's normal for the CPU to idle in the 40s and 50s, since AMD CPU's tends to run with high voltage at idle, and then drop in voltage under load. 

So, if you have an AMD CPU, I'd say 40s and 50s at idle is okay. If you have en Intel CPU, I'd say it's a tat high - but please understand that 40 to 50c in temps are perfectly fine and not dangerous at all. If you have poor airflow in the case, 40/50c isn't abnormal. 

I think you should focus more on what your temps are while under load, in a video games or when using a free benchmark program, such as Cinebench. 
The temps we would see here will tell us much more about how "good" your temps are. 

And back to the thing with you fan running really fast. I'm certain that your fan curve is too aggressive, when you only sit at 40/50c and your fans go full blast. 
Go into BIOS and tweak the fan curve

[JamesClark]

On 5/18/2021 at 12:08 AM, BetteBalterZen said:

If you have alright cooling, I'd say idle temps in the 40s to 50s with an Intel CPU, is a tat high. With AMD, and please correct me if I'm wrong, it's normal for the CPU to idle in the 40s and 50s, since AMD CPU's tends to run with high voltage at idle, and then drop in voltage under load. 

So, if you have an AMD CPU, I'd say 40s and 50s at idle is okay. If you have en Intel CPU, I'd say it's a tat high - but please understand that 40 to 50c in temps are perfectly fine and not dangerous at all. If you have poor airflow in the case, 40/50c isn't abnormal. 

I think you should focus more on what your temps are while under load, in a video games or when using a free benchmark program, such as Cinebench. 
The temps we would see here will tell us much more about how "good" your temps are. 

And back to the thing with you fan running really fast. I'm certain that your fan curve is too aggressive, when you only sit at 40/50c and your fans go full blast. 
Go into BIOS and tweak the fan curve

thanks again for the reply. I have an AMD CPU and I have no problem with the temps but with the rear case fan because it's like whenever I turn my pc on it will be like noisy but not noisy as a airplane engine and after some time it will spin so slow that you can follow the blade with your fingertips and making a razor sound. its not like that when the pc came whenever I run it its so quiet. and I did some research and know that 40/50c isn't for CPU and actually is pretty normal but for CPU at idle normally have 35/50c.

[BetteBalterZen]

3 hours ago, JamesClark said:

thanks again for the reply. I have an AMD CPU and I have no problem with the temps but with the rear case fan because it's like whenever I turn my pc on it will be like noisy but not noisy as a airplane engine and after some time it will spin so slow that you can follow the blade with your fingertips and making a razor sound. its not like that when the pc came whenever I run it its so quiet. and I did some research and know that 40/50c isn't for CPU and actually is pretty normal but for CPU at idle normally have 35/50c.

I can only guess on what might be the cause for the sudden increase in fan RPM but still, if you think it's running too fast, go into BIOS and set a fan curve.

[JamesClark]

i went to a shop that repairs Pc parts and yeah the rear case fan is broken, the bearings are broken and said that i need to buy new fan and now its working properly, thanks for the help tho i appreciate it good sir.