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Are iMac G5's supposed to be LOUD?

CubeHacker

CubeHacker

macrumors 65816
Original poster
Apr 22, 2003
1,245
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I received an iMac G5 the other day from a friend. However, the fans seem to go into crazy mode quite often. It starts out very quiet, then as soon as I start doing just about anything, they slowly ramp up to very loud levels. Watching a youtube video ramps it to max speeds in about 10 seconds.

If I set the system performance to "reduced" under energy saver, the fans stay at a much lower speed. However, automatic and highest cause the fans to get really loud.

Is this how the iMac G5's are supposed to sound? Its so annoying I can hear it from 2 rooms away. I remember reading reviews many years ago about how whisper quiet these iMacs were supposed to be. Or am I wrong?
 
o.k. there may be 3 reasons this is happening.

1.it is too hot in the room.

2.something may be inside that is in the way of the fan.

3.you are over working it(what is the processor speed?)

my emac (when it worked) did the same thing because someone put a plastic fork in it.
 
I think the problem is that those reviews are from several years ago, and since then computing has started to require more power. So your computer uses a lot of processing power viewing youtube (flash), which heats it up (the G5 was a very hot chip), causing the fans to kick in, which have probably gotten louder from a few years of use
 
Start with decent dust cleaning. Second what you can do is reapply thermal paste on CPU and GPU. Use high performance compound. This should help. iMac G5 under heavy CPU load (Handbrake for example) can be louder than when idle, but it shouldn't spin its fan to max rpm when it's doing "anything".
 
I've already opened her up and cleaned out all the dust. There was a TON inside, specially inside the main CPU fan and rear vents.

I used temperature monitor to check temps. The two highest that i'm seeing are
1.) Memory controller - usually sits around 78 C at all times(this has no fan)
2.) CPU - Idles around 60-65 when doing nothing, and peaks to high 70's low 80's when pushed to the limit.

I have no idea if these are "normal" temperatures or not for an iMac G5. I forgot to mention that its the 2.1Ghz model.
 
As 666sheep said, heavy load on the CPU such as encoding will cause the fans to ramp up.

If you want to hear the fans at true full speed, start it in Target Disk mode. It's like a wind tunnel compared with even a heavy CPU load on Automatic. Make sure the fans are spinning freely first though.

On mine, I found that the variation in fan speed on Automatic was very intrusive (not necessarily loud, just annoying), even when it simply wandered from idle to a modest speed. I left it on Reduced most of the time simply for that reason.

IIRC, the temperatures you've quoted are about what I had on a 2.0GHz.
 
I know my first generation intel Imac 2 ghz duel core's fan made a ton of noise on start up. But then was super quiet for the rest of the time. Sure its not your disk drive?
 
I'm 100% sure its not the disk drive =)

Its strange how some people here say that theirs was pretty much as loud as mines (especially on high load), and others that say theirs was whisper quiet. Perhaps some people got worse quality fans?
 
It might need a cleaning, I dunno because when I pulled my bro's core duo imac apart it was pretty clean inside.. one fan was a bit dusty but the others still looked fairly new. >>
 
Theres a couple of reasons for this:

1. Flash makes the fans ramp up on almost ANY Mac. I mean, a good 10 minutes of flash vids on my MacBook Pro and the fans are ramped up!

2. The G5 chip runs VERY hot. Thats why they have never made a G5 laptop :eek: And modern stuff like YouTube Flash probably stresses it quite a bit...

Its nothing to worry about, but I'm sure it is very annoying!
 
true 80 degree celsius is not that hot for a G5 processor , seen them going up further without any trouble , a mates 1.6 g5 iMac is usually at around that mark at idle since years , so cant be unusual as the imac works perfectly well since he bought it think 5 years ago , so i'd say if its a G5 iMac then as long as the cpu temp stays around that 80 degree mark everything is fine and for being loud hmm thats a tricky question ,for some sensible persons a fan running at 500 rpm is already unbearable loud ,while others dont have a noise problem when their fan is running at 2500 rpm
 
CubeHacker said:
...
Its strange how some people here say that theirs was pretty much as loud as mines (especially on high load), and others that say theirs was whisper quiet. Perhaps some people got worse quality fans?
Click to expand...

Possibly, although in my case when in was under stress it was definitely a whooshing (is that a word?) of air I was hearing rather than fan bearings.

And and I mentioned, when the machine was idling, on Automatic the fan would still wander between (say) 1500 and 2000 with slight variations in load. Even though it was actually very quiet at this point, I found the constant cycling up and down of the fan speed was driving me nuts, hence I switched to Reduced.
 
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hamster: my core duo 1,1 mbp idles at around 80c, that chip was pretty cruddy though hehe.

I don't think there is a massive problem here, the chips were quiet hot under load, so apple had to include some massive ass fans in there to move all the heat around, it won't effect the performance or longevity of the machine at all
 
Thanks guys. It seems that this is normal behavior for the iMac G5's. The only thing is that I guess one of the 3 fans has a rather annoying sounding bearing, which is causing it to become noticeably loud whenever it ramps up, which in this case, is quite often.
 
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