Bizarre CPU fan issues

Hi,

I've been having problems with my AMD Athlon XP 2000+ CPU overheating
recently so I bought a Akasa King Copper 824CU today.

I fitted the new fan and switched the machine on but before it tested the
memory the machine stopped and displayed "CPU Fan error" (or something like
it) across the middle of the screen then powered itself down. This happened
before I could access the BIOS.

I had no idea what the problem was as I connected the new cable to the same
power connector as the old fan (on the mobo). I then tried connecting the
old fan (lying loose in the system) into the mobo connector and new fan
(still on the CPU) onto a spare power connector - and it worked! This then
allowed me to get into the BIOS and I disabled "Detect CPU Fan Post" - I've
no idea what it does but I can now connect the new fan into the mobo power
supply and it works fine - so far it appears to cool the CPU by over 20 deg
C!

However the fact it detected a problem with this BIOS setting enabled
worried me. Does anyone know what the issue is and how to resolve it?

One other question... my old fan *seemed* to blow air out but the new fan
seems to suck air in - what is the correct way?

"Jase" wrote in message
...
Hi,

I've been having problems with my AMD Athlon XP 2000+ CPU overheating
recently so I bought a Akasa King Copper 824CU today.

I fitted the new fan and switched the machine on but before it tested the
memory the machine stopped and displayed "CPU Fan error" (or something
like
it) across the middle of the screen then powered itself down. This
happened
before I could access the BIOS.

I had no idea what the problem was as I connected the new cable to the
same
power connector as the old fan (on the mobo). I then tried connecting the
old fan (lying loose in the system) into the mobo connector and new fan
(still on the CPU) onto a spare power connector - and it worked! This
then
allowed me to get into the BIOS and I disabled "Detect CPU Fan Post" -
I've
no idea what it does but I can now connect the new fan into the mobo power
supply and it works fine - so far it appears to cool the CPU by over 20
deg
C!

However the fact it detected a problem with this BIOS setting enabled
worried me. Does anyone know what the issue is and how to resolve it?

One other question... my old fan *seemed* to blow air out but the new fan
seems to suck air in - what is the correct way?




looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

fans generally blow in....towards the cpu

"philo" wrote in message
...

looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

Ahhhhh.... that makes sense.

Why/how do new fans have a lower RPM but maintain such good cooling?

Jase wrote:
"philo" wrote in message
...

looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

Ahhhhh.... that makes sense.

Why/how do new fans have a lower RPM but maintain such good cooling?

Better effeciency

Kráftéé wrote:
Jase wrote:
"philo" wrote in message
...

looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

Ahhhhh.... that makes sense.

Why/how do new fans have a lower RPM but maintain such good cooling?

Better effeciency

It could also be that the tach signal from the new fan is 'dirty' and
not being read properly in the BIOS. Also, some fans draw more current
than the header on the MB can supply, which will cause problems. In
these cases, it's best to just connect the CPU fan directly to the PSU,
as you have done.
Just set the temp alarm in the BIOS and/or run a monitoring program to
look at the temps and/or voltages, and there won't be any problem if the
fan should fail and the CPU overheats. A good one is MotherBoard
Monitor:
http://mbm.livewiredev.com/

"Jase" wrote in message
...
"philo" wrote in message
...

looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

Ahhhhh.... that makes sense.

Why/how do new fans have a lower RPM but maintain such good cooling?



The one I used was physically larger than the old one...
so "pushed" more air but at a lower RPM

"philo" wrote in message
...

"Jase" wrote in message
...
"philo" wrote in message
...

looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

Ahhhhh.... that makes sense.

Why/how do new fans have a lower RPM but maintain such good cooling?



The one I used was physically larger than the old one...
so "pushed" more air but at a lower RPM


Talking about fans, my CPU fan that came with a 3GHz P4 runs at about
3300rpm (when the PC is more or less idle). At this speed it is quite noisy.
Is it possible to replace these? If so, any suggestions.
TIA

Have a look here

http://www.quietpc.com/

"Graeme" wrote in message
...
"philo" wrote in message
...

"Jase" wrote in message
...
"philo" wrote in message
...

looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

Ahhhhh.... that makes sense.

Why/how do new fans have a lower RPM but maintain such good
cooling?



The one I used was physically larger than the old one...
so "pushed" more air but at a lower RPM


Talking about fans, my CPU fan that came with a 3GHz P4 runs at about
3300rpm (when the PC is more or less idle). At this speed it is quite
noisy.
Is it possible to replace these? If so, any suggestions.
TIA

On Thu, 5 Feb 2004 17:05:55 -0000, "Graeme"
wrote:


Talking about fans, my CPU fan that came with a 3GHz P4 runs at about
3300rpm (when the PC is more or less idle). At this speed it is quite noisy.
Is it possible to replace these? If so, any suggestions.
TIA


Due to the design, incorporating the fan into a plastic shroud, it's
harder than it "could" be. You might put a resistor or series of
didoes, in series on the power leads, or take off the shroud,
carefully cuttin out the fan and leaving a flat hole where you could
attach the fan of your choice.

Alternatively you could just drill holes in the fins and attach the
fan with 4 L-brackets and screw/bolts, or just buy a new 'sink. It's
a shame that after all this time, intel still uses such a proprietary
'sink... I guess they think it looks cool.

"Bill Purvis" wrote in message
...
Have a look here

http://www.quietpc.com/

"Graeme" wrote in message
...
"philo" wrote in message
...

"Jase" wrote in message
...
"philo" wrote in message
...

looks like your bios is looking for a certain RPM
and the new, larger fan with it's lower RPM looks like an error

that happend to me onone machine and i had to update the bios
in order not to get the low RPM error

Ahhhhh.... that makes sense.

Why/how do new fans have a lower RPM but maintain such good
cooling?



The one I used was physically larger than the old one...
so "pushed" more air but at a lower RPM


Talking about fans, my CPU fan that came with a 3GHz P4 runs at about
3300rpm (when the PC is more or less idle). At this speed it is quite
noisy.
Is it possible to replace these? If so, any suggestions.
TIA



Thanks for the link. Is there any info on the performance of the Intel
supplied fan (airflow, noise, etc)? I'd hate to go and spend money on a
'quiet' fan just to find it's just as noisy as the one I already have.