Stand-by keeps CPU fan on

Question

When I select Turn Off Computer and Stand By my system goes to Stand By Mode. The HD spins down and the Green LED behind the Power on Off Button Flashes on and off as it always has. All fans used to stop: the system was perfectly silent. Now, the CPU fan keeps on going, making noise.
S3 powersave mode is configured in the BIOS. I did not update any drivers or system software.

And no, I won't accept 'this was designed for notebooks'! The working power-save mode is one the reasons I bought a Dell system.

Dell Dimenson 4400, 256MB RDRAM
Windows XP Pro Edition, Service Pack 1

Message Edited by PieterV on 11-26-2002 10:08 PM

tomintx · Answer

This is a pretty frequent question in the Forum, and the concensus of opinion, and probably stated somehwhere but I can't find right now, but it is normal for the fan to be running when in standby. Something to do with the new processors requiring cooling anytime they are powered. I can't speculate why it didn't do that before, every thing since the P3 MMX chip does this. You should though barely hear it, if it is noisy like a buzz or motorboat, then likely you need a new fan. Contact Tech Support. IF standby works for you, and you don't experience any problems on waking, then use it. There have been numerous problems reported however of waking the PC, where it does not respond, and Dell recommendation was to set standby to never in those cases.  If power consumption/cost is an issue for you then I would suggest you shut down the system/monitor and devices when you are going to be away for more then a few hours.

PieterV · Answer

@tomintx wrote:
This is a pretty frequent question in the Forum, and the concensus of opinion, and probably stated somehwhere but I can't find right now, but it is normal for the fan to be running when in standby. Something to do with the new processors requiring cooling anytime they are powered. I can't speculate why it didn't do that before, every thing since the P3 MMX chip does this.

The S3 powersave mode only consumes a few watts of energy throughout the entire system. The CPU + fin + fan are designed to handle about 40..50W when the CPU is active.
It makes no sense to state that the fan should stay on, there is simply no power that can generate heat. My system would have died months ago if there was because the fan has always been OFF during stand by.
I set the system to sleep when I have to concentrate on something complex (during programming) and this requires silence.

Pieter

Karell · Answer

Pieter, Thank you for using the Dell Community Forum. This is a Desktop hardware forum, if you are asking about a laptop system you need to post your question in the laptop forum. Try the Inspiron General Hardware or Bios boards for a start. As a general rule, when the laptop is on the fan will always be on. I believe it may be an issue with your bios settings, you may need to reset the bios settings and clear NVRAM. I have seen cases where laptop fans have always stayed on, and resetting the bios defaults fixes that problem. Post your question in the laptop forum to get exact information on how to reset the bios defaults and clear nvram. --------------------------------------------------------------------------

PieterV · Answer

@Anonymous_Karell wrote:
Pieter,
Thank you for using the Dell Community Forum.
This is a Desktop hardware forum, if you are asking about a laptop system you need to
post your question in the laptop forum.
I believe it may be an issue with your bios settings, you may need to reset the bios settings and clear NVRAM. I have seen cases where laptop fans have always stayed on, and resetting the bios defaults fixes that problem. Post your question in the laptop forum to get exact information on how to reset the bios defaults and clear nvram.

I'm actually talking about a Dell Dimenson 4400 (indicated in my first post).
Is it possible that the Bios and NVRAM reset has the same effect on a Dimension as on a notebook? How can I do this on a Dimension?

Pieter

Karell · Answer

Pieter,

It could, but I have never seen it do that on a desktop.
As far as I know the fan on a desktop is always on, no matter what...
You stated that the fan turned off before, did you see the fan shut off when you when into power save mode?
Could it be that the fan simply did not rattle before, and the rattling that you hear now
is what made you aware the fan has never turned off...
You are correct in the fact that the system and processor are designed to take a lot of heat.
But, unlike a portable that has all it's components designed to save power for battery life,
a desktop must keep it's fan running constantly to get rid of excess heat.

I have configured an Optiplex GX110 as follows.
Turn off hard disk after 3 minutes.
System standby after 5 minutes.
After the power saving features had activated, I checked both fans and they were still running.
I will do the same for my Dim_4100 at home and let you know what the results are.
As far as I know, fans on desktops only turn off when you totally shut down the power.

If you still wish to reset the bios defaults, here is how to do so.
--------------------------------------------------------------------

**Reset the bios defaults **

Entering System Setup:
Using the (Delete) key during the Dell logo screen the user may enter System Setup to make changes to the user definable settings. If having trouble entering setup using this key, try to press the (Delete) key when the keyboard leds 1st flash. Although not documented the old (Ctrl-Alt-Enter) key sequence will still work.

Resetting the bios defaults:
If you succeed you will get a screen that reads (Dell Dimension 4400 Setup)
One's in the BIOS setup, press the (F9) key, this will prompt you to ( setup Default Configuration)
Highlight Yes and press the Enter key.

Clearing NVRAM.
Press the right-arrow key to move to the Advanced menu.
Select the Boot Configuration submenu by pressing (Enter).
Press the down-arrow key to highlight Reset Config Data. Then change the setting to Yes.
Press (F10) to exit the program and restart the computer.

-------------------------------------------------------------------

PieterV · Answer

Two other Dimension 4400 systems (at work, one a little bit older, the order from the same date as mine) have the same behavior as mine had: all fans go down on stand-by. So it is possible and seems to be normal.
The BIOS and NVRAM reset did not solve the problem. Any other tricks (besides re-installation of Windows XP)?

asone · Answer

PieterV,  did you happen to play around with the bios when this problem started? I have heard that if you change the powersave setting in bios to S1 from S3, boot into windows, and then go back into the bios and undo the changes winxp will not enter a S3 power state without reinstalling the os.

PieterV · Answer

Thanks for you're replay.
The power save settings hasn’t changed. I did notice (when resetting the BIOS/NVRAM) that the event log of the BIOS has a "Pre boot error": memory size decrease. This happened some days ago and I think that the fan problem started at the same time. I ignored the error when it occurred and gave a reset. The system hadn’t been opened so it was a strange error.
I start to think that the power save mode S1 is used now, instead of the S3 mode. Is there any way to check this?

Karell · Answer

Pieter, Something else to try.Use the Configuration Jumpers on the motherboard to try and restore the bios settings.Diagram of where the configuration jumper is located here.Method 1: Maintenance Mode:1.Turn off the system and unplug everything.2.Open the system case.3.Move the jumper block from pins 1-2 to pins 2-3 on the configuration jumper.4.Attach the power cord, video cords, mouse, keyboard, and boot the system.5.It will boot you into the system bios, simply press F10 to save changes and exit. 7.When the system reboots turn it off and unplug the power cord.8.Open the system case. 9.Move the jumper block from pins 2-3 back to pins 1-2. 10.Put everything back together and test the system.Maintenance Mode (jumper pins 2-3) Maintenance mode executes POST and automatically puts the user into BIOS Setup. When setup is entered in this mode, additional setup menus and fields become available (unhidden) under the Maintenance menu. This additional menu area has a Clear Passwords selection. When in Maintenance mode, the system uses the CMOS defaults (not the User CMOS) to configure the system during POST. User CMOS settings are preserved during POST. When the user leaves Setup a message is displayed informing the user to 'Turn off power and reinstall the jumper in Normal mode position'. Method 2: Recovery Mode:1.Turn off the system and unplug everything.2.Open the system case.3.Pull the jumper block completely off the jumper pins.4.Attach the power cord, video cords, mouse, keyboard, and boot the system.5.Let the system sit for 15 seconds.6.Turn the system off and unplug the power cord.7.Replace the jumper black on pins 1-2 of the configuration jumper.8.Put everything back together and test the system.Recovery Mode (no jumper) In this mode, the BIOS will attempt to do a BIOS recovery. Neither the front nor the back lights light, but the fan does spin during recovery mode. --------------------------------------------------------------------------------

PieterV · Answer

The problem is solved!!! Google told me there is a utility called SUSPEND.EXE that can test the S1..S4 modes. An FTP searcher (http://search.ftphost.net/indexer/search.htm) gave me a path to the tool.
This tool puts a PC in each sleep mode for one minute. The S1 was OK, the S3 mode failed because of the mouse driver. I did an update of the Logitech mouse driver. The optical mouse was (and is) quite nervous and it was my hope that a new driver would fix this. It didn’t so I forgot that a new driver was installed.

So, now it’s a matter of getting XP to ignore the new driver and things will work as they used to be.

Thanks to everyone who was so kind to replay. All these tips pointed me to an excellent solution.

Karell · Answer

Pieter,

You are correct...I got to get my hands on a 4400, and the fans do go off during standby.
I think this may be related to the S3 power modes like "Asone" has stated.

1.Go into the system bios and change the power management mode to S1.
Then save changes and exit, and boot into Windows.
Then go back into the bios and change the power management mode back to S3.
Then save changes and exit, and reboot back into Windows.
Test the system.

2.Check the Windows power features.
Power Scheme Tab: Make sure that "System Hibernate" is set to never.
Advanced Tab: That the option "When I press the power button, " should be set to Turn off System.
Hibernate Tab: The option for Hibernate should be unchecked.

The_Namek · Answer

PieterV,
Interesting utility. I'm a bit surprised I haven't come across it in my web wanderings, but now that I'm aware of it I'll certainly be suggesting it to folks who are adamant about getting power management to work on their desktop PCs. Should be an interesting little experiment.

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Stand-by keeps CPU fan on

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