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Case Fans Running Too Fast

Hello everyone once again,

I have finally completed my build and you can check it out at http://
So far I am absolutely loving everything about this PC! When I run Bioschock Infinite on ultra settings at 1080p my GPU will range from 50-65°C and my CPU has never exceeded 55°C with stock fan (mind you it is running at 4000+ rpm and the CM Hyper 212 Evo is in the mail!) Anyways I have a 200mm front fan, 200mm top fan, and 120mm back fan. On automatic settings, my fans all run well exept the front 200mm runs at 2000+ rpm even when it's idling. I manually adjusted the front fan to 60% and my GPU and CPU temp stayed the same, so why is it running so fast on automatic?

Thanks you everyone!
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More about case fans running fast
  1. it's running so fast, likely because something is running hot in your system. In this case i'd say its because of the CPU.

    FX cpus don't report their core temps accurately, i suspect if you download HWmonitor you'll see the socket temp on the motherboard is nearing 70C... Get that new cpu cooler soon my friend... the stock cooler is not good enough to keep that 8 core beast cool.
  2. Whereisthefly said:
    Hello everyone once again,

    I have finally completed my build and you can check it out at http://
    So far I am absolutely loving everything about this PC! When I run Bioschock Infinite on ultra settings at 1080p my GPU will range from 50-65°C and my CPU has never exceeded 55°C with stock fan (mind you it is running at 4000+ rpm and the CM Hyper 212 Evo is in the mail!) Anyways I have a 200mm front fan, 200mm top fan, and 120mm back fan. On automatic settings, my fans all run well exept the front 200mm runs at 2000+ rpm even when it's idling. I manually adjusted the front fan to 60% and my GPU and CPU temp stayed the same, so why is it running so fast on automatic?

    Thanks you everyone!

    it may be becaus there not pluge in to a fan controller usually there are plugs for the fans on the mother board with fan controllers built in but thats not always the case so you can always buy an after market fan controller
  3. Thanks for the help guys, but I think I will wait until the new CPU cooler comes in and hope for the best. I wouldn't think that speedfan is giving a wrong CPU temp reading, but I could be wrong.
  4. Best answer
    Whereisthefly said:
    Thanks for the help guys, but I think I will wait until the new CPU cooler comes in and hope for the best. I wouldn't think that speedfan is giving a wrong CPU temp reading, but I could be wrong.


    Its not speed fan's fault. it's a problem with the whole bulldozer/piledriver lineup... technically it's been an AMD problem since the phenomII. See, with the PhII amd stopped using an actual thermometer to measure cpu core temps, and switched to a mathmatical algorithem. For the PhII this meant that temp measurements were often 5-20C off plus or minus. It didn't really matter cause you could roughly guess the "actual" cpu temp based on ambient air temps and socket temps on the motherboard... atleast narrow it down within a few degrees anyway.

    For the FX series however the problem is a bit more complex. see you get both temp inaccuracy like with the Phenom II AND a new problem unique to the fx lineup where the chip believes it's 255C or -255C or something insane when it's temp is above or under a certain point. My FX 8320 for example, when it's temp drops under 35C starts to report it's temp as anywhere from 5C - 10C, and while i have a great cpu cooler i don't have phase change unit so those temps are frankly impossible. As a result ALL piledriver/bulldozer cpu "core" temps should be treated as suspect until you know for sure it's accurate.

    The best tool for that is to check out the socket temp on your motherboard. Assuming your motherboard reports its temps properly (and when the piledriver is reporting it's temps properly) your motherboard's socket temps should be +10C hotter then the core temp. Generally your computer will start to temp throttle when the socket temp is reported around 72C-75C; and around 65C on the socket temp all the fans in your system will probably be running at or close to full blast.

    So if your cpu temp is being reported correctly by your cpu, then the socket temp should be hovering around 65C, which would cause your system's fans to spin up full blast.
  5. ingtar33 said:
    Whereisthefly said:
    Thanks for the help guys, but I think I will wait until the new CPU cooler comes in and hope for the best. I wouldn't think that speedfan is giving a wrong CPU temp reading, but I could be wrong.


    Its not speed fan's fault. it's a problem with the whole bulldozer/piledriver lineup... technically it's been an AMD problem since the phenomII. See, with the PhII amd stopped using an actual thermometer to measure cpu core temps, and switched to a mathmatical algorithem. For the PhII this meant that temp measurements were often 5-20C off plus or minus. It didn't really matter cause you could roughly guess the "actual" cpu temp based on ambient air temps and socket temps on the motherboard... atleast narrow it down within a few degrees anyway.

    For the FX series however the problem is a bit more complex. see you get both temp inaccuracy like with the Phenom II AND a new problem unique to the fx lineup where the chip believes it's 255C or -255C or something insane when it's temp is above or under a certain point. My FX 8320 for example, when it's temp drops under 35C starts to report it's temp as anywhere from 5C - 10C, and while i have a great cpu cooler i don't have phase change unit so those temps are frankly impossible. As a result ALL piledriver/bulldozer cpu "core" temps should be treated as suspect until you know for sure it's accurate.

    The best tool for that is to check out the socket temp on your motherboard. Assuming your motherboard reports its temps properly (and when the piledriver is reporting it's temps properly) your motherboard's socket temps should be +10C hotter then the core temp. Generally your computer will start to temp throttle when the socket temp is reported around 72C-75C; and around 65C on the socket temp all the fans in your system will probably be running at or close to full blast.

    So if your cpu temp is being reported correctly by your cpu, then the socket temp should be hovering around 65C, which would cause your system's fans to spin up full blast.



    I really appreciate your in depth description; I ended up trying hwmonitor and was receiving the same temps for my CPU and GPU so I think speedfan is on par. However, I can't wait for that cooler to come still because it is quite annoying having a heatsink fan running at 4000+ rpms, plus i would like to clock this CPU to 4.0 Ghz hopefully!
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