Legit Reviews

When powering on my computer, the fans run at high speed. Then (probably after POST) the fans slow to a lower (normal?) speed.
On occasion, the fans do not return to the slow speed. However, if I press the system reset switch, before the BIOS access prompt and before the system starts, the fans will return to the slow speed as the system starts up again.
If I just leave the fans running at high speed, "Speed Fan" (4.3.4) does show the higher speed but all temps are OK.

At what point in the power on/boot sequence do the motherboard temp sensors take control?
Is this a timing problem? Does the fan control "miss" whatever tells it that all is well?
Are the sensors faulty?
What else could cause this?

SYSTEM:
Case: Antech Sonata Plus 550 (550 W. PS)
MOBO: Intel D975XBX2, Version AAD53350-509
BIOS: BX97520J.86A.2831.0423.2112
CPU: Q6600 2.40gHz (not being OC)
MEM: 2GB, DDR2
COOLER: Zalman CNPS9500 AT
OS: OEM version, XP2 Home Edition, SP3
VIDEO: ATI Vision Tek Radeon X1050
MONITOR: 19" LG W1952 (using digital mode)
AUDIO: Using onboard audio
HD1: 160GB Western Digital SATA 2 (Not in RAID configuration)
HD2: 320GB Western Digital SATA 2 (Not in RAID configuration)
HD3: 300 GB Maxtor SATA 1
HD4: 200 GB Maxtor External USB

If you are using a Zalman CNPS9500 AT cooler then it should have a variable controler. Check your core temps with a program called core temp. If your rig is not overheating or your core temp is with-in range, what's the problem?. Once you put a after market cooler on your chip fan speed is controled by the variable controler. If you are talking about case fans then the fans will change speed on their own to regulate temps. This is normal. If temps are ok, don't worry about it.

Sounds like a BIOS problem if it's directly on startup.

How updated is your BIOS?

Dan

Looks like there might be a newer BIOS that you're currently running.
Might wanna give that a try.

http://downloadcenter.intel.com/Detail_ ... 6&lang=eng

I got a clue from another post that I saw somewhere.
My case is on a power strip that I turn off at the end of the day.

When I turn the strip on, even before turning on the computer itself, the power supply is applying 5 volts to the motherboard.
I guess that is for the "Wake to LAN". (?)

Anyway, if I wait after turning on the strip for a bit before turning on the case, the fans all run at the speed I would expect for a "cold start".

If I'm too quick on the trigger, the fans all run at max speed when I turn on the PC.

So far all seems good. We'll see.