reasons for a slow fan

[douglasb]

the front intake fan on my CM690 is acting wierdly.
its the stock one that comes with the case and its plugged straight into the motherboard.
looking at its speeds in HWmoniter its max is 1140rpm, minimum is 165rpm and current is 570rpm
iv had a look at it but cant see anything blocking
it is there any other reason it could be going so slowly?
thanks

[Infinite]

Age?

[douglasb]

Age?

about a month

[CaptainCrash]

Is the fan speed controlled by the motherboard's BIOS?

Maybe it's running at that speed because it doesn't need to go any faster? What are your temps like?

[this_is_gav]

Isn't it just the motherboard controlling it depending on heat?

[douglasb]

Is the fan speed controlled by the motherboard's BIOS?

Maybe it's running at that speed because it doesn't need to go any faster? What are your temps like?

systin - 31C
core 0 and 1 - 30C
core 2 and 3 - 25C
GPU - 56C
hdd 1 - 25C
hdd2 - 26C

i know they are all quite low but the other 2 case fans are both doing 1200rpm and i thought it was odd that one wasnt

[peterb]

Its contolled by the mobo - and operating normally
The hware monitor is not reporting the speed correctly
It is not being with the supplied with the correct voltage
The fan bearing is seizing up (unlikeley if it is only a month old)
There is some mechanical obstrucyion affecting it
All the fans are blowing into the case, and the air flow is such that the other two are forceing air out against the fan, slowing it down.

Of those, 1 and 2 are the most likely.

[Mithrandir]

If you have a spare fan, you could plug it in place of the slow fan and see what happens.

[CaptainCrash]

i know they are all quite low but the other 2 case fans are both doing 1200rpm and i thought it was odd that one wasnt

Maybe only one of the system fan headers can control the speed, the others run at full speed all the time?

What motherboard is it? Which headers are the fans plugged into? You're making us do rather a lot of guessing here...

[douglasb]

Maybe only one of the system fan headers can control the speed, the others run at full speed all the time?

What motherboard is it? Which headers are the fans plugged into? You're making us do rather a lot of guessing here...

sorry...

motherboard is an asus P5K premium wifi/ap
the fan is plugged straight into the motherboard, as are the others
iv tryed it in different headers
the fan is at the bottom front of the case, blowing in.
the other two fans are on the bottom of the case blowing up into the GPU and the other is at the top back blowing air out
there is nothing blocking the fan blades

im not too bothered about it as its not realy affecting the HDD temps (both around 26C) its just odd that it should be so low compared to the other two. i assumed that if the BIOS decided that the fans could slow down abit it would lower them all by a smaller amout and not one by loads?

[CaptainCrash]

I'm not familiar with that board, but IIRC Asus's Q-Fan can only control one system fan header in addition to the CPU fan. That doesn't explain why plugging it into different headers made no difference though... maybe it's just an odd fan after all.

If you want all the fans running at full speed (and the noise doesn't bother you), I guess you could try disabling Q-Fan in the BIOS... still, if your temps are OK there's probably not much point, as you say...

[ajones]

Maybe I'm showing my age here, but those temps look fine to me! Maybe the fan is running slow simply because it doesn't have to run fast?