CPU Cooling fan

  mikeyb59 19:26 13 May 2003

Simple question

Should the cpu fan blow into the heatsink or suck out?

Reason I ask is that I run an XP1800+ which under full load is consistently operating at around 55C.

I have 2 case fans blowing in but the cpu fan seems to suck out. Tried turning it over but it won't fit properly and the screws are too short.

Any ideas?

  Elrond 19:37 13 May 2003

I'm running an athlonXP 1800 with fan blowing in and still running at 50C.

  graham√ 19:44 13 May 2003

Turn one of the case fans round so the highest one is blowing out. This will give a better air-flow. Check the fan blowing in is not sucking air from a radiater. I would guess the CPU fan is designed to only fit one way.

  Mysticnas 19:50 13 May 2003

i assume you just keep it with label side up....

i've just modded my CPU fan. well not really modded, but more like getting 2 HSF 1 with a good fan and the other with a good heatsink and putting the best of the two together.

a 6000Rpm fan on full copper dual heat-pipe heatsink.

ready to overclock my CPU! ;)

  -pops- 19:50 13 May 2003

If you have two case fans, the front one (low level) sucks in and the rear one (high level near the CPU) blows out.

If you have one case fan it is best placed at the rear at high level.

If you have more than one case fan there should be and equal number drawing air in as blowing air out.

Be careful not (as someone reported the other day) to have a rear fan drawing air in, fresh from a hot radiator.

The CPU fan draws air in the correct direction as supplied and it is best not to mess around with it however you, yourself, think it should fit. There is most likely a good reason that you are unable to fit it in reverse.

55 degrees is not particularly high for that CPU but you may well get it lower by adjusting the case fans as I suggest.


  24863423 19:58 13 May 2003

XP1800 fans can only be fitted one way, it is easy to see which way they are fitted by the 'step' on the bottom of the heatsink which should fit against the CPU socket 'step'.
55 does appear to be a little high for an 1800 but not above what it can manage. Whichever way the air is blowing is gonna be right. Only time to really worry is if the heatsink feels cold, as it indicates that it is not in full contact or doing the job.
Long answer but fairly correct i think as I work with these cpu's and fans daily. Hope it helped.


  mikeyb59 20:07 13 May 2003

Wasn't really worried about the temp as I knew it was well within AMD's specs. Was trying to lower it as I had seen others with lower temps using this cpu.

Will try the suggestion of reversing one of the case fans when I get home tomorrow.

Thanks again to all who responded. Will let you know how I get on.


  mikeyb59 15:16 14 May 2003

Turned one of the case fans around as suggested - seems to have lowered temp around 4C.

Still seems a little on the warm side but not worrying about it.

Thanks to all for the help.

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