Posted 04 June 2009 - 08:24 AM
If it was "built" then I am assuming a desktop.
I know of a Compaq laptop that was spinning up the circulation fans sometimes and understand all that now...
So, a whine sounds like something spinning. Things that spin are fans, hard disk drives, CD drives.
Healthy hard disk drives should probably not be changing RPMs while in normal operation and are are generally quiet (but XP power settings may come into play), CD drives should not be spinning if they are empty, so that leaves fans.
On my system, I have fans in the power supply which run constantly and do not change speed. If the PS fan sounds started to change, I would think it is time to replace it.
I have a system fan, a fan on my CPU and a fan on my video card.
Depending on things like the type of motherboard, BIOS options, third party software, etc. these fan speeds can be adjusted as the temperature changes. Some software can monitor temperatures of such things and adjust the fan speeds (increase for too hot) and then decrease when the temperature gets back to normal.
You can open your case and see what your situation is. When you hear the whine, figure out who is whining and then figure out (or ask you builder) if your system has the capability enabled that would allow the fan speed to adjust according to load and/or temperature. If yes (probably), you know what is happening. If you don't like it, set the fans to always run at the highest speed that eliminates the possibility of overheating.
My BIOS has a "Cool 'N Quiet" feature that adjusts the system and/or CPU fans when it needs to and cranks them up when the temperatures increase. I just have that feature set to always run cranked up. The switching back and forth is not a problem, but I found it annoying, so the safest option for me is to always run as cool as possible.
It is really a fairly common feature.
The mediocre teacher tells. The good teacher explains. The superior teacher demonstrates.