Question Should I change the CPU cooler or the case fans?

Aug 9, 2020
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Background:
I'm currently using a PC I built way back in 2009 with a few changes along the way.

CPU: AMD Phenom II X4 955 BE with stock cooler
Motherboard: Asus M4A79 Deluxe
Case: Nzxt Guardian 921 (2x 120mm intakes and 1x120mm exhaust)
Thermal Paste: Arctic Cooling MX-2
GPU: Sapphire RX560
Storage: 1HDD and 1SSD

No OC. Cool n Quiet enabled. A month ago the CPU fan started getting really noisy. So I checked the CPU temp with HWiNFO. It was idling at 61deg. Apparently, that is the cutoff temp for this CPU. So I replaced the thermal paste. This dropped the idle temp to less than 50deg. Surprisingly the 11 year old tube of paste still works fine.

Some crude testing:
Used CPU-Z for stressing the CPU and HWiINFO for monitoring temps and RPM. Ambient temp ~28deg. I tried using different combinations of the Asus Q-Fan option from the BIOS. Here are the results. I didn't take screenshots of the readings. Just noted them down.
(Sorry I couldn't figure out how to make a compact table.)

CPU Q Fan Mode​
CPU Fan RPM​
Case Q Fan Mode​
Case Fan 1 RPM​
Case Fan 2 RPM​
CPU Temp​
Noise​
Under Load
Off6550Off1300110054.5Vacuum cleaner
Performance5000Performance100090057.5Extremely noisy
Optimal4650Optimal95085059.5Very noisy
Silent4560Silent80070061Noisy
Silent4300Performance95097560Bearable
Silent4250Off1075122559Bearable
Idle
Off6250Off1300120044.5Vacuum cleaner
Performance4400Performance99084046.5Noisy
Optimal4000Optimal88077047.5Bearable
Silent3950Silent77062048Ok

So, I'm currently using the Silent/Off Q-Fan combination, which seems to be the best trade-off between temp and noise. I tried using speedfan to see if I could increase the case fan RPMs and drop the CPU RPM, but there was no manual control even after disabling Q-Fan from the BIOS. And neither does HWiNFO show the fan control icon. So I guess I'm out of luck with this motherboard. I want to squeeze as much out of this PC as possible. The PC will likely be used soon at ~40deg ambient. The 12deg increase in ambient will probably give an almost direct increase in the CPU temp and get it throttled.

Question:

Would it be worth it replace the cooler with say, a Noctua NH-U9S for better direct cooling for the CPU? (Cooler has to be <=150mm in this case or it's going to touch the fan on the side panel.)
Or should I replace the case fans with say, 3 x Noctua NF-S12B 1200 3-pin for more cold air into the case ?
I don't want to take both and spend double the cash. So, which option would be better in keeping everything cool and quiet?
 
Aug 9, 2020
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Yes, I think the case fans are working fine. Although, I don't remember what RPM they used to be. Maybe I could take them out once and add a little engine oil to the bearings, just in case. That should get them back to shape, while I change the cooler.

Thank you! I'll post the updates once I'm done with the exercise.
 
I'm currently using a PC I built way back in 2009 with a few changes along the way.
Sure, you can get a better cpu cooler. That would help with temperatures slightly.
But ...

Ultimately you should be thinking about replacing core part of your system - cpu, motherboard, ram.
CPU is outdated and a power hog. It wasn't very good even, when it was released in 2009.

PC case is really bad in terms of air flow. Obstructed intake. I'd replace case too.
 
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Aug 9, 2020
24
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Sure, you can get a better cpu cooler. That would help with temperatures slightly.
But ...

Ultimately you should be thinking about replacing core part of your system - cpu, motherboard, ram.
CPU is outdated and a power hog. It wasn't very good even, when it was released in 2009.

PC case is really bad in terms of air flow. Obstructed intake, small fans. I'd replace case too.
Yes, I will be getting a new build soon. Will be giving this PC off to the kids for as long as it goes. It's served me well for this long. Let's see how much longer it can go.
 
Aug 9, 2020
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I re-lubed the case fans with engine oil. Vibrations disappeared totally. Noise levels are noticeably lower. Did the same testing again. Ambient temp ~28deg. After the last time, figured the case fans were better off with Q-Fan turned off. So I changed only the CPU Q-Fan. Here are the results.

��
CPU Q Fan ModeCPU Fan RPMCase Q Fan ModeCase Fan 1 RPMCase Fan 2 RPMCPU TempNoise
Under Load
Off6250Off1240131053.5Vacuum Cleaner
Performance4750Off1240131056Very Noisy
Optimal4350Off1240131057.5Bearable
Silent4050Off1240131058.5Ok
Idle
Off5750Off1240131042Vacuum Cleaner
Performance4125Off1240131044Bearable
Optimal3575Off1240131045Ok
Silent3560Off1240131045Ok

Just a reminder... The three case fans are DC running at 12V. Out of these the side panel fan doesn't have an RPM reading, just the front and rear ones. And only the CPU fan is PWM.

With Q-Fan Off for the case fans, their RPMs are constant throughout. I probably swapped the front and rear case fans. That would explain why the RPM dropped for one and rose for the other. In which case, both fans got a slight RPM boost after re-lube. The idle temps seem to have dropped 2.5 deg and the load temps around 0.5-1 deg. Could be because of any/all of the following: (1) slightly better airflow with the reduced wobble/vibrations (2) minor rpm boost (3) clean fans (not much build-up to begin with though). CPU Fan RPM dropped around 200-300 with a corresponding drop in noise levels.

Overall, more than the temps, the noise levels are much better after re-lube. Already ordered the Noctua NH-U9S. Hoping to get it in a few days. Will post the improvement after setting it up.
 
Aug 9, 2020
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Got the Noctua NH-U9S. Installed it and repeated the tests. Couldn't hear a thing, even with Q Fan turned off. The temps dropped 2deg in idle and 4.5deg under load. Not much change there with the temperatures. But man was it quiet!! The stock cooler had to scream it's lungs out to get anywhere near the noctua! And I had no idea what I was putting up with all these years!
��
CPU Q Fan ModeCPU Fan RPMCase Q Fan ModeCase Fan 1 RPMCase Fan 2 RPMCPU TempNoise
Under Load
Off2033Off1270135049Quiet
Performance1215Off1270135053.5Quiet
Idle
Off2033Off1270135040Quiet
Performance1115Off1270135042Quiet

Thank you guys for your suggestions and sticking around. Can someone tell me how to mark this thread as closed?
 
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