Low RPM CPU fan monitoring in the BIOS

greenmachine33

Junior Member
Dec 8, 2001
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A friend has just built a new system Soyo Dragon KT266A board with Athlon XP. I am considering A7V266-E or P4B-T, but have a question about how the BIOS in the Asus boards monitors CPU fan RPM.

What my friend did was put in an 80mm Panaflow quiet fan on the CPU and run it at 7V, with an 80-60 airflow converter on a 60mm heatsink on the XP. At 7V the Panaflow runs at about ~2000 rpm. He has gotten excellent case and die temps, just as good as a noisy 4500 rpm 12V conventional CPU fan. 80mm fans are quieter than 60mm for the same CFM, and running it at half speed makes it yet quieter again.

Both him and I are insterested in (1) stable, (2) reasonably quiet system and lastly (3) solid performance (but not going for the last 5%). I'm not OC'ing at all and am not a serious gamer.

The only issue with this setup is the Soyo Dragon (I think Award-based) thinks that 2000 rpm is a non-working CPU fan, so it shuts down the system (which is why you first have to boot with the fan at full speed and shut off the CPU rpm detection). Now of course, if his fan suddenly stops he'll never know (since you can't hear it anyway :) and we'll have fried Athlon XP .... I'm sure you've seen the pictures on the net.

==> Does any one have any experience with the Asus BIOS for A7V266-E or P4B-T whether they will detect slower running CPU fans properly, and/or allow you to set the RPM threshold?
 

Lonny007

Member
Jun 12, 2001
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hmm if you run into that problem I would disable that feature in bios, and download fre mother board monitor, it is free and a very nice addition to most all computers, while your bios might have problems this program should not. Check it out!
http://mbm.livewiredev.com/
 

Mikewarrior2

Diamond Member
Oct 20, 1999
7,132
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Greenmachine33,

Can i inquire as to how your friend is reading DIE temps? Which Motherboard is he using?



Mike
 

greenmachine33

Junior Member
Dec 8, 2001
6
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Thanks, lonny007 that's a good tip. I'll grab that.

The only thing is, I assume this is a program that runs under Windows. So if you're using it on an AMD system, my assumption is that by the time the OS loads (20 secs) from cold boot, if the HSF is bust, the CPU will have already been toasted. ??? For the P4 not so much of a problem, because allegedly they have builtin thermal protection, so probably it'll boot through to Windows and you'll see the problem on the monitor.

Ideally, the BIOS will detect a fan running below some soft-set RPM threshold, and shut-down & refuse to boot at all.

BTW, is that fre? Fire? not sure exact spelling.

Thanks, Dave
 

greenmachine33

Junior Member
Dec 8, 2001
6
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Mike,

Good question. He's using a Soyo Dragon Via KT266A-based MB, with Athlon XP. I don't have the exact model number handy.

He's reading the temp directly from the BIOS the Soyo ships with, nothing fancy. I believe the temp probe was just a paste-on case temp sensor that came with the Soyo. Nothing fancy, it's certainly not the onboard die temp diode of the XP, allegedly no one except Siemens supports reading that for Athlon XP.

So is the temp lying? Probably. Except the CPU heatsink was cool to the touch and the outside case is cold. Also we're looking at the relative temps compared to a conventional cooling solution.

- Dave

 

greenmachine33

Junior Member
Dec 8, 2001
6
0
0
I should update you all on a new development:

I have since first posting, just recently ordered the P4T-E based system. So I'm going with Intel....

Turns out, building a quiet Intel system seems a little easier. I listened to a brand new Socket478 fan that comes with the Intel standard retail box - seemed quite quiet actually, nothing nearly as bad as the older P2, P3 fans. Someone knowlegeable told me that my noisiest component would be a 7200rpm drive! Recommended the Seagate Baracuda 4.

So here's what's coming (should have it by Friday):

Asus P4T-E socket 478 i850 (400MHZ FSB)
512MB Rambus ECC (yes I know, a ripoff)
P4 1.8G with the standard retail HSF & sink
Seagate ST360021A baracuda 4 7200 rmp HDD
Enermax Whisper 350W 2 fan P/S
Enermax manually adjustable RPM 80mm case fans (2)
.. plus a couple of optical drives & misc

Plan is to leave the CPU fan alone, and muck with the settings of the case fans till I get reasonable all round temps. Upgrading heatsink/fan on the P4 is not so easy - not a lot of aftermarket stuff available here. All the OCers go for AMD. Plus the CPU straps looked like they'd be in the way of an 80-60mm funnel converter ?

I'm picking up a radioshack noise-meter so I can compare it to my old machine (my old machine sounds like a jet engine in need of an oil change)

Most people agree this will provide me a reasonably quiet system, yet solid high-end performance & super stable. We'll see what "reasonable" is on Friday :)

Thanks! - Dave


 

Jhhnn

IN MEMORIAM
Nov 11, 1999
62,365
14,681
136
So far as your friend's system goes, he should be able to disable that "feature" in the bios, save the changes, and not have to fuss with it again unless he restores the bios defaults for some reason.

I wouldn't worry about frying the cpu. Just the sink alone will keep things under control while booting to windows, then MBM will take over. If the HSF assembly somehow comes off, the chip will fry anyway, whether the fan is spinning or not....