As a new linux user the main thing keeping me from a full switch and recommending others to switch as well is that I cannot get my Compaq Presario S5000NX desktop (Celeron 2.4GHz) to decrease its fan speed. This computer is in my family room and the noise from the 100% fan speed is really bothersome when watching TV or talking.

I am running SUSE 9.3 (free FTP version).

As I understand it, having ACPI correctly configured should fix this, providing my BIOS supports ACPI. So, here is what I could find out:

When I enter BIOS it says it is PhoenixBIOS Core version 4.06, Revision 3.21, however compaq.com (actually HP.com) says that the BIOS is provided by ASUS/Award. Their support page also shows my computer as having an ASUS P4G533 Motherboard with S3 Power Management Support.

/var/log/messages shows the following for ACPI:
Power Button: on
Fan1 on
Thermal Zone (-270ºC)
Supports 8 throttling states
Processor CUPO supports cl

/proc/acpi/info: version 20040715

/proc/acpi/sleep: S0 S1 S2 S3 S4 S5

In YAST-->Hardware-->Hardware Info it shows:
APM is not supported or enabled
is_pnp_bios:yes
lba_support:yes
CPU shows ACPI flag

So, any ideas on how to adjust and get this thing running? Since my BIOS doesn't have an option to turn on cool'n'quiet or anything is it possible a BIOS update would help? If so, what update should I look into - Phoenix, Award or Asus? Is there a file I could edit to tweak it? Also, the biggest problem is probably the chassis fans. Any recommendations are welcome.

Depending on the type of noise I suppose you could benefit from having a new fan put it. You may have a fan problem (ballbearing and/or such).

I imagine that I could get a high-end fan that would have less noise when running full speed. I would prefer not to have to get new hardware, though.

What I am hoping to be able to do, however, is get the fans I have to perform as they do when I use Windows on the same machine. The fans run full speed during the boot sequence and then throttle back to next to silent during normal use.

If I could even get the fans to throttle back just during a standby/sleep mode in Linux it would make a world of difference.