Power Mac G4 Cube 450MHZ Noise!

Could be a hard drive failing sound, or it might be fan noise.

Failing Hard Drive Sounds http://datacent.com/harddrivesounds.php

Listed by drive manufacturer. Click on the > next to the drive & you will hear the typical failure sound.

How to Tell When Your Hard Drive is Going to Fail
http://www.lifehack.org/articles/technology/how-to-tell-when-your-hard-drive-is- going-to-fail.html

Grinding And Clicking – Symptoms Of A Failing Hard Drive
http://pcperformancetools.com/getdata/grinding-and-clicking-symptoms-of-failing- hard-drive.html

Failing Hard Drives
http://losangelescomputerhelp.com/computernetworkingnews/failing-hard-drives.html

Some newer Macs use a technology called S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) to attempt to detect problems with the hard drive that indicate it is about to fail, such as mechanical wear. If a SMART-equipped (SMARTReporter.app; Mac OS X 10.3.3 or later; at least one ATA, SATA or eSATA hard disk drive) computer detects that its hard drive is about to fail, it can warn you of this so that the data on the disk can be backed up.

 Cheers, Tom 😉

There may be a way someone has retrofitted a display card that has a fan, but it is a lot of work and not too likely.

The stock cube does not have a fan as standard equipment, but there is a bracket for a large flat fan in the bottom of the enclosure. One may have been added.

Tom \[Texas Mac Man]'s suggestion of a failing Hard Drive is the most likely. The spindle bearing may be complaining of the extra heat. ? Got a recent backup? Now would be a good time to make one.

Hi, Garry -

If you have a disk in the optical drive, try ejecting it. If the noise (vibration) stops, then it is probably the disk - some, especially older ones, can have an unbalanced label.

Garry Westwell-

When other folks come looking for answers after finding your discussion here, what should they try to help resolve an issue like this?