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Cpu fan reading low rpm's

  • CPUs
Last response: in CPUs
January 13, 2009 8:01:53 PM

A while ago I purchased an Intel E8400 with a gigabyte GA-P35-DS3L/S3L motherboard. Shortly after building it I started noticing that my idling temps were a little high according to the program coretemp (this is the only program I used to check and it idled around 53 degrees C and went up to 70 degrees C when gaming) so I decided to reapply thermal paste since I was using the paste that came with the processor and reseat the hs fan. When I rebooted, and I don't know if this was the problem beforehand or not I guess I did not pay much attention, the cpu fan was running at only around 180-200 rpms. Leaving it in bios for around 10-15 minutes the processor only got to 34 degrees C but the system temperature (don't know if that matters) was raising to around 41.

Also, just to test it I plugged an AMD fan that a friend had into the port and the RPM's were still low at around 300 but they were slightly higher than my Intel readings. I also plugged the cpu fan into a free system fan port and the rpm's were around 800-900 steady while sitting in BIOS.

I ordered a new cpu fan to try out and I'm hoping this fixes the problem but if it doesn't I would like to know what is going on.

My questions are these:

1) Does that sound like a misreading on the speed or is the fan running that slow?

2) If the port is broken, can I use the extra system fan port I have as a backup?

3) How fast should be cpu fan run?

4) Does replacing the fan sound like a good idea?

Now I do not claim to be a computer expert. My computer was assembled under supervision of friends who know more than I do. I just want to fix it if there is a major problem.


More about : cpu fan reading low rpm

a b à CPUs
January 13, 2009 8:25:58 PM

Make sure that you have disabled fan control in BIOS.


Look under "PC Health Status"
Then go to "CPU Smart Fan control", set this to "Disable".
January 13, 2009 8:43:29 PM

Yeah the smart fan control feature is disabled. The fan just sits between 186 and 187 rpm's while the temp fluctuates between 30-31 Celcius. Do a get an accurate idle temp if i'm just in bios?
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a b à CPUs
January 13, 2009 8:50:13 PM

Run Prime95 Small FFT and see if the fans kick up.
January 13, 2009 9:58:18 PM

How long should I run it?
a b à CPUs
January 14, 2009 10:27:43 AM

20-30 minutes.
January 16, 2009 2:06:54 PM

Alright I replaced the stock intel cpu fan with an aftermarket one and the BIOS reports that is running at 216 rpms now which seems low still. I ran Prime95 while I was sleeping last night and I kept Everest open to monitor the temperatures. The strange thing about Everest is that while my BIOS reports my new cpu fan is running at around 216-218 rpms, Everest reports that it is running in the 860-870 rpm range. Anyhow, idle temps reported with Everest are Core 1 = 41 C and Core 2 = 37 C. Seems they jump up to around 60 while running Prime 95. Now I really don't know which temperature program is the best since coretemp reads about 5 degrees hotter and realtemp read 5 degrees cooler than Everest. Here is the screen shot of what I was looking at when I stopped the test this morning.

Is my BIOS just not reading correctly? I have not yet flashed the BIOS, could it just be an old version that doesn't read right? I want to overclock a little bit but I want to make sure my system is stable first and my temps are in the safe range.

Thanks for your help so far Shadow....

a b à CPUs
January 16, 2009 10:23:13 PM

Looks to me like a defective fan header. Go with the RealTemp readings. Flasing BIOS may help, run CPUZ and see what version you have.
January 17, 2009 1:31:21 AM

Looks like version F9B.....

Does it matter if it reads correctly or not? Can I just maybe plug it into the system fan port?
a b à CPUs
January 17, 2009 7:26:34 PM

Ah.... that might be a problem. The stablest BIOS version I have tested is the F8f BIOS version. You can't find it on the Gigabyte website, check Google. Yeah, try on another port too.
January 17, 2009 8:50:08 PM

K i'm using F8f now which did not fix the cpu fan sensor issue so I plugged the fan into a different port and its running at 1462 rpm so that sounds good. However, I ran into a new problem. I accidentally broke a fan blade on the fan!!! It is still keeping it fairly cool now I just need to order a new stupid hahaha

But yeah, looks like it is a faulty header and they won't replace mobo for that will they? Not a big deal, it is staying at around 58 C with full load and I even overclocked a little to 3.42. Should I just keep it plugged into the fan that reads the faster speed?
January 18, 2009 4:53:59 PM

Alrighty then. Thanks again for your help Shadow!