View Full Version : CPU Fan stops working in win2k !?!?!?

11th October 2000, 23:56
Very strange problem !!.. as soon as windows 2000 starts booting (just after showing the windows logo ) the cpu fan stops running !!
and remain off untill i shutdown or restart.
Win 2k is the final retail and installed in ACPI mode.
I have win98 SE on the same PC and the fan works ok in there ( but the win98 isn't isntalled in ACPI mode )
Win NT 4.0 server is also installed on the same PC and the CPU fan works great.
What's goin on between Win2k and the CPU Fan ?
I checked in power management applet in control managemeent and changed between all the different power schemes .. but nothing changed.
also i have changed the option in bios which turns the cpu fan off during suspend .. also no difference.
i checked too the cpu throttle speed and it's at normal.
While in win2k the cpu temp is higher than that of win 98 by 1-2 degrees according to mother board monitor. 38 C vs. 36 C.
but when i touch the heat sink .. i feel it's more like a 10 degrees difference. it's just cool in win98 and rather warm to hot in win2k.
i checked the MS site and searched the KB and the only thing their says that win98 doesn't support passive cooling (reducing CPU speed instead of running a fan )
so i guess win 2k is try to passive cool my CPU ? but the cpu speed is the same 450 MHZ checked by cpuid and mother board monitor.
i really don't wanna run my cpu w/o a fan and this prevents me from using win 2k
any help plz !

Ooops .. forgot to mention system specs !
giga-byte 6BXE mobo bios 3.4
celeron 300A@450
128 PC-100 cas 3 sdram
Matrox MGA-G200 8 MB SD.
realtek 8139 pci
SB 16 PnP
ATX case and PSU 250 W

[This message has been edited by arbymo (edited 12 October 2000).]

[This message has been edited by arbymo (edited 12 October 2000).]

12th October 2000, 02:19
Have you tried running it for like 30 mins or so and giving the CPU some work to do? Does the fan ever come on? It's possible that the fan's being controlled via ACPI and it just doesn't think it needs to be on.


"Life is what we make of it, yet most of us just fake"

12th October 2000, 06:39

12th October 2000, 07:14
What Admiral has just shown you is an "always on" CPU fan power plug. Hehe.

If you're not overclocking, I'd let the CPU get good and hot to see if the fan kicks in. All fans nowadays have thermal monitors on them.

- Gurm

Listen up, you primitive screwheads! See this? This is my BOOMSTICK! Etc. etc.

12th October 2000, 07:54
Actually most (>95%) fans today do not have thermal monitors. Only the specialized ones do.

Electric Amish
12th October 2000, 08:21
What kind of fan is it?

Also, like suggested by The Pit, you could hook it directly to the PS instead of through the motherboard.


12th October 2000, 09:20
thanx for the reply guys http://forums.murc.ws/ubb/smile.gif
well .. i just ran prime95 in the torture test mode for about 30 mins.
the cpu utilization was of course 100%, and it got realy really hot BUT the fan didn't kick in !!!
i couldn't put my finger over the heat sink for more than 2 secs. the strange thing is the cpu temp was only 42 C.
and i looked every where in the bios and found no options for the fan threshold.
the only settings is the cpu duty cycle and it's set at normal (other settings are 12.5%-65%)
and i don't think the fan has thermal monitoring coz MBM 4.17 doesn't report it.
MBM doesn't even reprot the cpu fan in win2k, although it reports it in win98.
I hate it when windows thinks it's smart enough to think for me ! and it doesn't give u a choice even !
not a registry key or an UI setting.
it's in the ACPI specs that the temp threshold for the cpu should be in the GUI and also the choose between passive and active cooling .. looks like MS didn't implement that !!
Admiral that fan converter looks cool .. i dunno if i can find it here (egypt: it's hot too !!) but the 3 pin fan allow it to be off in standby in most OS's.
i searched at MS site .. all over the net .. but i can found are info about ACPI specs.

[This message has been edited by arbymo (edited 12 October 2000).]

12th October 2000, 09:22
by the way .. anyone knows what's the news group for giga-byte boards ??
and wat's the news group for general mobo discussion ??

12th October 2000, 10:44
Do the simple thing and use admirals suggestion.

[This message has been edited by The PIT (edited 12 October 2000).]

12th October 2000, 14:03
I think the yellow wire on fans is for thermal monitoring.

arbymo: that convertor is about 0.4$ here (Romania), I'm using three of them. One for the 486 fan on my vanilla and two for the CPU fans.
You should be able to find one there, just try searching, asking people, you never know where you might find one http://forums.murc.ws/ubb/wink.gif For my CPU fans I went to the three biggest and most respectable retailers here in Bucharest and they didn't had any good ones, I went to smaller retailers and they didn't had any, I went to a friend of my father's who runs a small store (he sells used PC components) and he sent me to a... kind of a general hardware store. Sunon fans heaven, from small 40mm fans to 120mm ones (if only I could find a big enough heatsink http://forums.murc.ws/ubb/frown.gif). Also found some thermal grease there.
Search http://forums.murc.ws/ubb/wink.gif

[This message has been edited by Admiral (edited 12 October 2000).]

12th October 2000, 16:20
There maybe a setting in the bios that allows the fan to be turned off if the machine thinks the cpu is cool enougth.

12th October 2000, 17:22
Ad is correct, the yellow is the tach out lead.

12th October 2000, 17:38
Thanks for the great help everyone.
PROBLEM SOLVED through bios update !! http://forums.murc.ws/ubb/wink.gif
Well i had the just before latest bios and was under the impression that there is no difference between the last two more than a built in VGA bios for the GA-G400 cards.
But i just met a friend of mine who has the same mobo and had the same problem as me and he told me the new bios fixed it.
HURRRAAAAAAAAAAYYYYYYYYYYYYYYYY http://forums.murc.ws/ubb/smile.gif))))
posting from win2k now http://forums.murc.ws/ubb/wink.gif
If they just write what fixes and changes they do in their bioses }:
Just to note .. this is the 1st time that a bios update really solves a problem for me.
Gigabyte also released a bios flash utility that works like a charm under windows.
anyway .. thanx again everyone and hope u luck with winblows and lazy support guys ;p
hehe .. not all of them are.

12th October 2000, 22:43
isn't yellow 12 volts, black ground, red 5 volts and blue tach monitoring?
or is it different from fan to fan?