CPU Fan reving up/down randomly

[AnAngelsDeath]

My parents computer is a bit old, its a Socket LGA 775 Pentium 4 3.2Ghz. I've begged them to let me build them a new system, but they say it works for them. Except the fact that the CPU fan revs up and down on its own even when its been idle for hours. It gets really friggin loud sometimes. I've used different programs to tell me what the temps are at under load and idle, and they are all normal, no reason for the fan the be reving up so it sounds like a damn jet engine when its just been sitting idle for a few hours, or even when your just browsing the net. Any suggestions on what this could be ? Been building computers for years and never experienced this. I checked the BIOS as well and the temp according to the BIOS is perfectly normal as well. I tried to see if there was a fan control or like Cool n' Quiet, SmartFan type option in the BIOS but I didn't see it.



i really wish they would just let me build them a new system lol.....but thanks in advance for any helpful replies, since they refuse to upgrade, i at least wanna get this fixed, or have them get a new fan for me to install if that turns out to the only fix.

 

[Eureka!]

The revving sounds like the fan profile is sitting on its hysteresis point. Try using speedfan (or similar) and building a custom fan profile. Since they are not gaming, it doesn't really need to be super cool. On my system, I have my fans running at minimal voltage (35%) to keep it spinning all the way until around 50°C, at which point I ramp up to 100% at 65°C. You could do something similar to that, and you could probably place the 100% point just a bit south of the maximum temperature. It will run hot but quieter.

Also have you checked the inside of the case? Make sure it isn't dusty or anything.

Well, a P4 is pretty good for most usage, I bet if you just clean up the computer a bit, install a cheap SSD and reinstall windows it'll be good as a general use computer for quite a few more years. You also have an option of upgrading a few things to keep the computer relevant, if it really is old. The 775 socket goes all the way through 2008, so you have a lot of variety in CPUs. Figure out what the newest processor that motherboard will take and drop in a used one. You can find a Q6600 for $50 or a E7500 for $30. If you can, add in a gb of RAM, add the SSD, and the computer will be more than relevant for the next 3 years. Also a cheap CPU cooler will cost you less than $10 on sale, I found my CAFA50 for $5 after rebates and that's a full tower 120mm cooler.

 

[AnAngelsDeath]

well they kinda game. My step-dad is a huge fan of the Original Doom games, and I got him Doom 3 awhile ago, so he plays that on there as well as Age of Mythology. I play WoW on it sometimes if I am spending the night. But WoW and Doom 3 are as hardcore as the gaming gets on it. And he only plays maybe once or twice a week for an hour or two. And I spend the night maybe once a month if that.

Anyways. I will give that a try and see how it works out and post my results. Thanks for the info brother.

Got my degree in Computer Science/IT and Certified in CISCO Networking, and I can't figure out how to get this fan to STFU lol Go figure

 

[AnAngelsDeath]

So I am back at my parents for the weekend and am bored, so I am making another go and trying to fix this damn fan issue before I just say screw it and buy a new one, which obviously is prolly the best route to go, but I like solving problems/puzzles, and I have this kinda OCD thing about not finishing up a problem once I start it, so I just really want to try and fix the damn thing, even tho I am buying them a new one.

ANYWAYS. I have downloaded SpeedFan, and familiarized myself with it somewhat. So far I've tried just temporarily reducing the CPU fan speed to a lil less the 50%, no matter what the temp is, and even with that it ton drop below 3200 RPM and is still hella loud. For a Brief second I got it to about 2800RPM and it sound almost as quite as it used to. But that didnt last like i said. So I am not sure what else can be done. Any other ideas as to why this fan seems to want to keep reving up and down from between 3,800RPM to 4,500RPM ? As well as Ideas on how to stop this from happening.

 

[colinstu]

Download an application like Realtemp or Coretemp and look at what kind of temps are being reported from that CPU. Idle for that sucker should at least be under 50C (pretty generous. closer to 30 would be ideal). Load it should be under 80C (maybe under 90... P4s loved those high temps lol). The temps should be under those numbers, maybe a little close to them.

Regardless, I'd take off the HSF, clean off any dust on it, clean off all the old TIM on the CPU and HSF, and put on a fresh application + install hsf.

If the fan was fine before, but just recently it's been revving up like crazy, the TIM between the CPU and HSF probably got disturbed or's just crusty & old. Lowering the speed of the fan when the CPU is probably screamin' hot (why it's trying to cool itself off all of a sudden) isn't healthy for the CPU.