i have an "Xtreme Switching power supply" that came with my desktop tower. it is a 400watt psu. and when i start it up it mkes a buzzing noise and the noise slowly starts to become lower and lower until it becomes into the normal "working" sound. it takes about 3-4 min for the buzzing sound to dissapear. i dont know what the problem is...but im thinking it is prob slowly dieing on me. no wonder it came with the dsktop" well my computer is on for about 8-10 hrs a day ...if that might be of some help any suggestions will be appreciated!

Notwithstanding that a switching power supply is noisier than a regular PSU, it still could be devloping some problem. Does it work ok otherwise? Most switching supplies will have a buzz to them, that's normal. If it has always done this and seems to be working fine, I probably wouldn't worry about it. Yet. Let's see what others have to say. HTH :)

All computer PS's are switching power supplies - if they weren't they'd be larger. heavier, and much more expensive. Assuming this is a recent problem and has not been there since new, sounds like the bearings on the PS fan are starting to go. The fan is a standard size and easy to replace. Are you SURE the noise comes from the PS? It could come from any failing fan, or even a noisy CD drive if there is a CD in the drive when you boot. Open the case, start it up from cold after it has been off a while, and make sure that's where the noise come from.

My Antec 430w has started the "groan_during_powering_up" noise and will quiet down to a whisper when the PC has been "warmed-up". From what I have read about other people having this same problem, it seems like the most common cause is the bearing(s) of the fan(s) is(are) going out, either by, overheating or nearing it's life expectancy. I have replaced the fans and the noise has ceased. If your PS is still under warranty, I would RMA it and get a replacement. If not, open that sucker and replace it. HTH

hehe, you beat me to it Mike :)