Rear fan constantly slowing down/speeding up

Hello all,

first of all here is the hardware I am using

CPU: Phenom II X4 955 Black
Windows XP SP3

The problem I have is the fan in the rear of the case is LOUD and it is constantly slowing down, then speeding up and it just keeps cycling over and over. Been happening for about a week now.
I have tried using AMD Overdrive and SpeedFan to adjust fan settings but nothing has worked as of yet.

My voltage is set to 1.4v
I have enabled ASUS Cool n Quiet in BIOS

I never really figured out how to configure speedfan. My motherboard doesn't have a guide on their site. If anyone has any suggestions to help I would greatly appreciate it.
If more technical information is needed just let me know I can provide it.
18 answers Last reply
More about rear constantly slowing down speeding
  1. Turn off the cool n quiet and see if that helps.
  2. memadmax said:
    Turn off the cool n quiet and see if that helps.

    The cool and quiet was off at first I tried enabling it thinking it will help solve the issue and it didn't.
  3. I tried OCing my system a long time ago.. that's why I tried going into AMD Overdrive to see if something was oc'ed too much. I'm pretty sure I have set everything back to their default values though so I don't think anything is overclocked anymore.

    However everytime I open Overdrive it has my fans set to Manual and 100%. No matter how many times I choose Automatic and hit save, they still say Manual when I reopen the program. Not sure if that has anything to do with it though. Hope they aren't being overworked for nothing.

    The weird part is it happens in the middle of the night too when I don't have any programs open and the computer is actually in screensaver mode so why would the fan be struggling?
  4. This problem only recently began? How old is the fan? Try replacing it with another one, or temporarily connect it directly to the PSU (if it came with a molex adapter).
    Uninstall Speedfan and use only whatever Asus sent with that mobo (original AI Suite perhaps?)
  5. The problem began about a week ago. The whole computer is 2 years old. All the parts were bought together and put together myself.

    Ok, I completely disconnected that fan from the power supply.
    The sound is gone (of course).
    Core Temp is 111°F
    I will look into buying a new fan but honestly I don't feel like I'm short on fans. If you look at my case ( it already comes with 4 fans.
    So that's 3 I'm left with + the heatsink.

    I've never had a fan go bad but do you think that the cause of it slowing down like that was from a setting on my computer or did the thing just die?
  6. Getting two years out of a cheap fan is not bad.
  7. Looks like I'll be looking into replacing that fan. I should have just unplugged it along time ago. For some reason I thought the fan was acting weird because I was messing with SpeedFan and messed up the setting for it.

    I have an extra fan in an old computer case in storage I'll try hooking it up to this machine and see if I still get the same issue tomorrow.

    Appreciate the help everyone I'll update after I do that.
  8. Well I haven't gotten a chance to test out another fan yet but earlier today my GPU and core both got to 144°F and one of the fans got really loud.

    I've been getting BSOD a lot more frequently than normal too. It's almost always been giving me the ntfs.sys error message on these blue screens lately.

    I ran memtest and I did find errors on both sticks of RAM I have which are G.skill so they have lifetime warranties. Do you think they are the cause of all this?
  9. What brand and model (not just wattage) is your PSU?
    Bad RAM will cause BSODs, but not make fan speeds vary. A bad PSU can do all sorts of things, including killing other parts (like the RAM).
    Another fan getting loud could just be your system trying to cool itself. Make sure you have good airFLOW through your case (typically front to back; a side fan is usually an intake and a top fan should be an exhaust). Make sure your front fan is an intake.
  10. This is my case here:

    It has two side fans, 1 front and 1 rear. no top fan.

    My power supply is 630W -
  11. Your PSU is fecal. I would not trust it to reliably power computer components.
    Your system with a 9800GT can be powered by a 380W Antec or 400W PC Power & Cooling.
    Edit: It is amazing how many computer problems can ultimately be traced to a bad PSU.
  12. Why do you say that it is a bad CPU? At the time I bought it with the other parts it seemed like it had decent wattage and good reviews.

    Are you saying the psu isn't capable keeping my computer stable? I was actually wondering if it might be the psu too.. but it's not like I have top of the line parts running under it
  13. Not the CPU...the PSU...Power Supply Unit. Raidmax is not known for quality, in fact it was one of their units featured in an old Corsair clip that died well under its labeled rating (they showed three dying in that clip, all with sparks and smoke). You may not be stressing yours in a way that would kill it outright like that, but it was likely built without proper EMI filters, and using substandard parts such that it is not capable of producing clean and stable output voltages.
  14. That was a typo sorry I meant to say PSU.

    There's not really any way to find out if the PSU is the issue unless I buy a new one and swap it right? Don't have any higher watt PSUs laying around unfortunately.
  15. You don't need higher wattage, you need higher quality. A 380W Antec Earthwatts would be sufficient to reliably power your rig.
  16. Ok. I don't think I have any higher quality ones either since they are stock. I thought I was buying a good one when I got that raidmax one lol.

    I will look into finding a new one. How do the raidmax psu's have such good reviews on newegg? That's normally what I go by for hardware that I don't know exaclty what to look for.
  17. IMHO (there are a few others), the best sites for competent technical PSU reviews are and; close behind (good load testing, but may not dissect) are and Newegg PSU reviews are meaningless consumer fluff. Someone will buy a 500W Raidmax, Coolmax, Logisys, Diablotek, Apevia, CM, etc; then put a 200W load on it and write a glowing review.
    HardwareSecrets also has some good tutorial articles.
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