Question CPU fan goes insanely fast at boot but never anywhere near as fast even when CPU usage is 100%

[Phil3371]

I just bought myself a used i7-4790K recently, it was a nice upgrade from my extremely old i7-930. Went from 2.8Ghz to 4.0 Ghz base core speed but I'm starting to regret it. Just working on a video editing software that brings all 4 cores usage to max when transcoding, it very quickly brings my CPU TEMP a little over 90 degrees celcius in a matter of a few seconds. It stays stable at 90-93.

What I don't get is why my CPU FAN never goes above 2000 rpm, which is a very low speed based on the ZERO sound it makes at that speed yet when I'm booting my computer, for just a couple seconds, my CPU FAN goes insanely fast to the point of generating a lot of noise but just a couple seconds. So I know that the fan is capable of reaching a very fast speed but it actually never does. Even in the BIOS, when I select MAX SPEED, the fan's max speed caps at 2000 rpm, very low speed if you ask me, given that it makes zero sound. I just don't get it. How come my fan never decides to give me this INSANE speed THAT I NEED to cool down my CPU???So frustrating!!!

My fan tells me every time I boot that it's capable of spinning insanely fast like it's showing off all it's capabilities yet it will let my CPU die and never trigger that speed when IT IS REALLY NEEDED. Talk about bad engineering? My motherboard is a MSI H97 GUARD-PRO and my CPU FAN is the same type as my old i7-930, a round shaped Intel heat sink with a round fan on top. I'm a long time ASUS fan. I don't know if it's a MSI problem but it's the first time I'm not happy.

I was happy with my ASUS P6T i7-930 when even at MAX USAGE, cpu temp never went higher than 75 degrees even when overclocked! I guess I will have to check under the hood and try replacing the thermal paste but it enfuriates me, when I KNOW that my fan could speed up and fix this issue. It can speed up but it just won't.

Arrrrrgh!

 

[Lutfij]

Welcome to the forums, newcomer!

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

My motherboard is a MSI H97 GUARD-PRO
If there's the option to replace the board, I'd ask you get a Z97 chipset motherboard and pair it with a DDR3-2133MHz dual channel ram kit to get the most out of your Haswell refresh platform.

 

[Phil3371]

Welcome to the forums, newcomer!

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

My motherboard is a MSI H97 GUARD-PRO
If there's the option to replace the board, I'd ask you get a Z97 chipset motherboard and pair it with a DDR3-2133MHz dual channel ram kit to get the most out of your Haswell refresh platform.

Thanks. I'll keep it in mind for next time. I've had my old computer for 15 years and am pretty poor. I actually didn't have any need to upgrade, I was just a little scared that my old one could die so old it is. I just wanted to treat myself with a little upgrade that cost me almost nothing to jump from 1st gen to 4th gen. Definitely not spending more money for at least 2 more years where I might jump to 8th gen if I find another good deal. I'm on Linux, dropped Windows ever since Microsoft bullied everyone, started forcing everyone to TRASH their old computers for nothing. So it was an easy choice to boycott microsoft and now proudly running on Linux Mint 22.1. As you can see, I'm not a gamer. LOL.

 

[JayGau]

Thanks. I'll keep it in mind for next time. I've had my old computer for 15 years and am pretty poor. I actually didn't have any need to upgrade, I was just a little scared that my old one could die so old it is. I just wanted to treat myself with a little upgrade that cost me almost nothing to jump from 1st gen to 4th gen. Definitely not spending more money for at least 2 more years where I might jump to 8th gen if I find another good deal. I'm on Linux, dropped Windows ever since Microsoft bullied everyone, started forcing everyone to TRASH their old computers for nothing. So it was an easy choice to boycott microsoft and now proudly running on Linux Mint 22.1. As you can see, I'm not a gamer. LOL.

It's not bullying, it's how computer technology works. Operating systems are getting more powerful, more complex and thus harder to run, so old hardware can no longer be supported. And I am not even talking about security concerns.

Even Linux at some point has to end support for old stuff. It happened to me when a version of CentOS deprecated an older RAID protocol and some of our drives were no longer detected, or some old computers lost the display because their display adapter was no longer supported.

It's frustrating when you don't have enough money to follow the train, but old hardware and software can't be supported forever.

 

[bill001g]

Check the bios settings. Hard to say on the older machines but modern ones have fairly advanced fan control. Not sure when you run linux but there is a free program called fan control that allows a lot tuning of fans.

In the end it likely does not matter. I forget the exact limits on these older CPU but I suspect you are not hitting the thermal limits. Load hwinfo and see. It will actually tell you if the cpu is hitting a thermal throttle limit. If it is not hitting a limit then it really doesn't matter if you were to find a way to drop the temperature say 5 degrees would still run the same except your fan would be making more noise.

If you find no other option I suspect you could just get some kind of power adapter that lets you connect the cpu fan directly to the power supply. The fan would then run at 100% speeds. I suspect on a machine as old as yours it still has some 4 pin molex plugs and there are many common fan adapters for those

 

[Phil3371]

Check the bios settings. Hard to say on the older machines but modern ones have fairly advanced fan control. Not sure when you run linux but there is a free program called fan control that allows a lot tuning of fans.

In the end it likely does not matter. I forget the exact limits on these older CPU but I suspect you are not hitting the thermal limits. Load hwinfo and see. It will actually tell you if the cpu is hitting a thermal throttle limit. If it is not hitting a limit then it really doesn't matter if you were to find a way to drop the temperature say 5 degrees would still run the same except your fan would be making more noise.

If you find no other option I suspect you could just get some kind of power adapter that lets you connect the cpu fan directly to the power supply. The fan would then run at 100% speeds. I suspect on a machine as old as yours it still has some 4 pin molex plugs and there are many common fan adapters for those

Yep, the throttle limit is 100 and has not yet reached it but it's a little close for me... I do have a cool fan control in my bios for a computer this old, much better than the zero control I had with my even older ASUS P6T. I can select inside a graphic, 4 thresholds to increase temperatures and it is working. It's just that the very maximum fan speed I can get is 2000 rpm, the equivalent of gently blowing air on your forehead. lol! Yes, it's a 4 pin connector cpu fan but I don't think it's molex plug, it's slim like the slim 2 pin connectors, practically the thickness of a jumper. But thanks, reassuring a bit. I might leave like this since I didn't pay much for it and it is not reaching max temp so far...

 

[Paperdoc]

I think you are worrying for no reason because you misunderstand the info. But to be sure I understand, I believe you say this is an older Intel CPU cooling fan you are still using. although you have not specified exactly what model.

First, 2000 RPM is NOT a slow fan speed. That is a normal full speed for many fans. Not sure exactly for YOUR unit.

Secondly, you report that you get a LOT of noise on start-up that stops after a short time, and then the fan stays quiet. This sounds like the first stages of fan bearings wearing out. For an older fan, the sequence usually is:
1. Fan makes a lot of noise when started up on a cold system, but that noise lasts from 10 to 60 sec. Then the noise stops and does not return while running. If you reboot, the noise does not happen. But if you shut down and let the system cool off (a few hours?) the noise is there again on the cold start.
2. As time goes on, the period of start-up noise gets longer.
3. Eventually the noise never goes away no matter how long you keep running. It even is there on a hot reboot.
4. Fan becomes always silent because it has seized up and it NOT turning ever, so you get NO cooling!

The reason for all this is that the fan bearings slowly wear out with age, making the bore in the sleeve bearing larger while the shaft remains the same because it is a harder steel material. At some point this enlargement is enough that the shaft "rattles" in the looser bearing. But in early stages, the running fan warms up the shaft and bearing, expanding the shaft more than the bearing and the extra space shrinks, so the shaft stops rattling around. As long as the system stays warm, it is silent. When it cools down completely, we get back to a loose bearing situation so it makes noise again on a cold start. Over longer time the looseness gets worse, so it takes longer to warm up the bearing to the silent condition. Over longer time even that is not enough to stop the rattling. REALLY badly worn bearings cannot keep the unit working and it overheats so much it seizes right up.

If that is what you are seeing at the beginning stage you should plan to replace that unit - you cannot replace just the motor bearings. But you do not need to do this immediately. Normally such a worn system will take up to a year (maybe longer) to get to the always-noisy stage. But then you DO need to replace BEFORE the fan seizes and gives you NO cooling.

 

[Phil3371]

I think you are worrying for no reason because you misunderstand the info. But to be sure I understand, I believe you say this is an older Intel CPU cooling fan you are still using. although you have not specified exactly what model.

First, 2000 RPM is NOT a slow fan speed. That is a normal full speed for many fans. Not sure exactly for YOUR unit.

Secondly, you report that you get a LOT of noise on start-up that stops after a short time, and then the fan stays quiet. This sounds like the first stages of fan bearings wearing out. For an older fan, the sequence usually is:
1. Fan makes a lot of noise when started up on a cold system, but that noise lasts from 10 to 60 sec. Then the noise stops and does not return while running. If you reboot, the noise does not happen. But if you shut down and let the system cool off (a few hours?) the noise is there again on the cold start.
2. As time goes on, the period of start-up noise gets longer.
3. Eventually the noise never goes away no matter how long you keep running. It even is there on a hot reboot.
4. Fan becomes always silent because it has seized up and it NOT turning ever, so you get NO cooling!

The reason for all this is that the fan bearings slowly wear out with age, making the bore in the sleeve bearing larger while the shaft remains the same because it is a harder steel material. At some point this enlargement is enough that the shaft "rattles" in the looser bearing. But in early stages, the running fan warms up the shaft and bearing, expanding the shaft more than the bearing and the extra space shrinks, so the shaft stops rattling around. As long as the system stays warm, it is silent. When it cools down completely, we get back to a loose bearing situation so it makes noise again on a cold start. Over longer time the looseness gets worse, so it takes longer to warm up the bearing to the silent condition. Over longer time even that is not enough to stop the rattling. REALLY badly worn bearings cannot keep the unit working and it overheats so much it seizes right up.

If that is what you are seeing at the beginning stage you should plan to replace that unit - you cannot replace just the motor bearings. But you do not need to do this immediately. Normally such a worn system will take up to a year (maybe longer) to get to the always-noisy stage. But then you DO need to replace BEFORE the fan seizes and gives you NO cooling.

Although I have no trouble imagining this cpu fan could be old, I'm pretty sure the noise it makes at boot is not because of wear. As I said, my older PC has the same TYPE of fan, it looks the same and YES, my older PC's fan is all worn out with heavy grinding. It's a completely different sound. My worn out fan makes a low frequency uneven grinding noise, easily recognizable as an old worn out fan with shot bearings. But this new, old PC I bought that has a fan that looks identical, the noise it makes at boot is a completely different noise. It sounds more like a very high frequency rotating tool like a dremel at high speed. You can hear it gradually yet still very fastly increasing its speed for 2 seconds then coming back down then kind of adjusting itself, spinning a little faster then a little slower. Just with the noise, you can hear it's a high rotating speed sound then the fan slows down to pretty quiet. I admit, it's not quite ZERO sound like I said but pretty quiet. This fan looks new, very clean and the blades look new beloved patriot and span clean. I can't imagine ever being able to clean my worn out fan on my older pc that clean so new this fan looks like. It's always the same noise AT BOOT, not during restart. I have to shutdown then start the PC for the fan to behave this way and no matter how long the pc has been running or how many times I shutdown/restart the pc while still hot, it's the same 2 seconds sequence. It really sounds like it's a programmed sequence. It's always the same sequence. I'm including a picture of the fan. My old eyes have troble reading the model numbers. I see ?97 378 001. And no, there's no cables touching the fan. I put in a brand new EVGA 750W power supply.

P.S. I can't seem to find how to attach a file from my pc, I can only attach from the web?

 

[SkyNetRising]

My motherboard is a MSI H97 GUARD-PRO and my CPU FAN is the same type as my old i7-930, a round shaped Intel heat sink with a round fan on top.
I'm a long time ASUS fan. I don't know if it's a MSI problem but it's the first time I'm not happy.

That is not ASUS nor MSI problem.
It is Intel stock cooler problem. Stock cooler is fine for i3 and barely sufficient for i5,
but completely inadequate for i7.

Get yourself a decent heat-pipe tower style cooler.
Deepcool AG 400, Cooler Master Hyper 212 or similar.

 

[Phil3371]

That is not ASUS nor MSI problem.
It is Intel stock cooler problem. Stock cooler is fine for i3 and barely sufficient for i5,
but completely inadequate for i7.

Get yourself a decent heat-pipe tower style cooler.
Deepcool AG 400, Cooler Master Hyper 212 or similar.

I agree with your assessment. I often read that those Intel coolers are not good enough and I have also read how the 4th gens are known for generating a lot of heat...

It still baffles me however how that Intel fan has the ability to spin faster than 2000rpms yet that speed is unattainable during normal operations. Only at boot.

 

[Misgar]

when I'm booting my computer, for just a couple seconds, my CPU FAN goes insanely fast to the point of generating a lot of noise but just a couple seconds.

Are you sure it's your CPU fan? I have at least one PC where the GPU fans spin up to maximum for a few seconds at POST, then stop running altogether until I run some intensive GPU tasks. It's the GPU BIOS checking the fans are working.

You need a decent heatsink on an i7-4790K as these graphs imply. 123W stock. 141W overclocked. I have three i7-4770K systems and they all use less power than your CPU.

https://www.tomshardware.com/reviews/core-i7-4790k-devils-canyon-overclock-performance,3845-9.html

For cheap big air cooling, my favourite is the Thermalright Phantom Spirit 120SE (7-heatpipes) or the Peerless Assassin 120SE (6-heatpipes). You'll need a large case though.

https://www.amazon.com/Thermalright-Phantom-Spirit-120-SE/dp/B0D949MRNM

https://www.amazon.com/Thermalright-Peerless-Assassin-Technology-1850RPM/dp/B0DRFT6MK3

I've also used the Thermaltake SI-100 low profile 6-heatpipe cooler in a home theatre system, but on an i7-4770K. With only a single 120mm fan, the SI-100 might not be enough to cool an i7-4790K at 140W+ overclocked. Haswell CPUs get hot quickly under load. I guess it's Intel cheaping out by using TIM instead of Indium solder between the die and the IHS.

https://www.amazon.com/Thermalright-SI-100-TL-E12B-Bearing-Technology/dp/B0BRTLJD8F

In comparison, my AMD 7950X dissipates 170W at 93°C (200°F) in Topaz Video AI 4K renders under a Noctua NH-D15 cooler. I know I could do better with a 420mm AIO, but I prefer air to liquid.

 

[Phil3371]

Are you sure it's your CPU fan? I have at least one PC where the GPU fans spin up to maximum for a few seconds at POST, then stop running altogether until I run some intensive GPU tasks. It's the GPU BIOS checking the fans are working.

You need a decent heatsink on an i7-4790K as these graphs imply. 123W stock. 141W overclocked. I have three i7-4770K systems and they all use less power than your CPU.

Yes, I have just checked again. It's my CPU fan. My Nvidia GTX 1660 SUPER spins gently from power on to normal operations. Thanks for all the heatsink info but buying a better heatsink might cost me more than I paid for the entire used pc! Well I learned a few things. If I had known, I might have went for a 6th or 8th gen used pc instead... But thanks to everyone's help I learned important stuff for my next buy...

 

[SkyNetRising]

For cheap big air cooling, my favourite is the Thermalright Phantom Spirit 120SE (7-heatpipes) or the Peerless Assassin 120SE (6-heatpipes).

Phantom Spirit and Peerless Assassin are complete overkill for i7-4790K.
$30 - 4-heatpipe/single fan tower cooler fill be perfectly fine here.

 

[Paperdoc]

OK, bearing wear is not a problem. You should note this. For ALL mobo fan headers the NORMAL start-up behaviour is that every fan is told to start up at full speed to be SURE it does start. The header checks the fan speed signal it gets back to look for NO speed which indicates failure. A failure triggers an on-screen warning and, for the CPU_FAN possibly more drastic intervention. As the whole POST process completes, every header's control system then kicks in with a reading of the actual temperature on the relevant sensor and sets the proper fan speed according to that info. So EVERY fan starts at full speed on any start-up, then reduces to proper speed after 5 to 15 sec. Note that I said EVERY fan, so the combined noise difference is noticeable. MAYBE you mistakenly assume ALL the noise then is due to that CPU fan alone.