G5 makes "fan power up" sounds every few minutes

[Morgan19]

I'm working on a new G5 and just had something very odd start happening to me this week. Every few minutes or so (literally), it'll make a "whir up" sound while I'm working... The best way I can describe it is that it's as if a fan is starting to go faster, or on the sound a PC makes right after you put a CD in the drive and are accessing it... It's that kind of gentle "aiplane" noise that starts quietly and builds for a few seconds and then quits. I've checked my power settings and the computer isn't set to hibernate or anything, and this does it constantly while I'm working. (It might do it while I'm not here but since I wouldn't be around then, I can't tell.) There's no noticeable change in performance when it makes this noise, or anything else out of the ordinary.

Like I said, it sounds like a fan spinning up or something but I can't seem to figure out why it's doing it. It happens constantly so it's not like the system is suddenly under load or anything. Any ideas what it could be, and why it just started this week?

m19

 

[bassplayrr]

You compare the sound to that of when you first install a CD, so this may be a dumb question, but do you have a CD in the drive when you hear this noise? Sometimes when I leave a CD or DVD in the drive for prolonged periods of time the drive will do that 'whir-up' noise a it does when I first inserted the disk. Other than that all I can assume is that your CPU is just warm enough to kick in a fan, yet not warm enough to keep the running for long. You may also want to confirm in the 'energy saver' settings that your CPU is set to automatic and not highest as highest will often increase the fan noise.

-Chris

 

[Morgan19]

You compare the sound to that of when you first install a CD, so this may be a dumb question, but do you have a CD in the drive when you hear this noise?

I wish it were that simple. Unfortunately no, there's nothing in the CD drive.

Other than that all I can assume is that your CPU is just warm enough to kick in a fan, yet not warm enough to keep the running for long. You may also want to confirm in the 'energy saver' settings that your CPU is set to automatic and not highest as highest will often increase the fan noise.

That's a good point, might very well be it. I checked and the CPU setting is at automatic, but I also noticed there's a setting for "Reduced." I think I'll tick that and see if the noise still happens. If it doesn't, I'll know that's what's causing it.

Thanks,
m19

 

[Avid6eek]

I just purchased my first Mac a few days ago and I experience the same thing on a regular basis. The PowerMac is by no means a quiet system. As far as I can tell there are 3 seperate thermal zones in my system. One for the Burner/HDs, One for he PCI/Graphics cards, and one for the Processors. If either one of these zones gets above a set temperature, the fans spin up.

The loudest spin up is the CPU zone. This happens randomly...I can be viewing a webpage, or opening an IM client. It is definetly related to CPU load, as it only happens when I'm doing something. Kinda sucks that it's happening now in the winter...my computer room is 65F. During the summer it gets as warm as 95F.

If this is something that just started happening, it is possible that something has changed. Are the fans at the back of the system blocked at all? How old is the system? it may be time to open it up and clean it out with a can of compressed air. Have the ambient temperatures changed recently?

 

[Morgan19]

Nothing's changed, no. The case has been where it's at for about a month (which is as long as we've owned it) with no changes in just about anything. When I dropped the processor usage down to Reduced, it didn't make the noise. So at least I'm positive now.

What's really weird is that it only happens for a few seconds at a time... Is that even enough time for the fans to do whatever cooling they need? Seems like it should be constant or at least longer than that, if it's heat.

m19

 

[Acill]

Welcome to our world of being a G5 owner mate. I have a 2.5 dual that does the same thing. If it happens ALL the time over and over you could have a bad board. Apple will replace it. Give them a call. Mine does it too, but installing more RAM did the trick of preventing it as often. I have 3GB in mine now. I'd also recomend you visit the online G5 user group at g5support.com for some more info and some great support from those of us lucky to have a G5.