iMac 1.8 G5 20 inch--What are Normal Temps

Question

Level 1

7 points

iMac 1.8 G5 20 inch--What are Normal Temps

I thought I would just take a poll on what my normal operating temps should be for a 20 inch iMac G5 with a 1.8ghz and a 250gig hard drive. I have been worried that this thing is cooking inside. I may just be used to my cooler running G4 MDD (steady 55 C all the time). This iMac is currently sitting at about 144F but will spike to about 160F when playing games etc... The hard drive temp is what is really worrying me...constantly sitting between 130F and 138F. Is this normal...Just do not want to have to buy another hard drive in the future. Is there a way...or should I say should I attempt to adjust the fan kext file to adjust the fan speed at different temps like I did on the MDD...(sorry, the question mark key is stuck and will not work)...

Thanks much,
Robert

MDD Dual 1.25, super, combo, 2 gigs, Mac OS X (10.4.10), 12" PowerBook, 2 iMac 1.8 20 inch G5s

Posted on Sep 14, 2007 3:50 PM

Answer 1

MGW

Level 7

27,083 points

Sep 14, 2007 4:39 PM in response to RRack

Hello again Robert - Assuming that it's a Rev A, they are perfectly normal temps, don't worry and don't mess with the ktext file. If you think it's running too hot (and it isn't) lower the processor speed the in Energy Saver pref pane.

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Answer 2

Bosco45

Level 1

15 points

Sep 14, 2007 10:07 PM in response to RRack

Robert,

You're correct to be concerned about temperatures, especially HD temps approaching 140F, which most drive manufacturers insist is the upper limit for drive longevity. Lowering the processor temperature will reduce HD temp and anything you can do to lower the temperatures WILL increase the chance of longevity of your machine.

The iMac G5 PPC's appear to run at the very edge of acceptable temperatures, due in part to the heat generated by the G5 970 processor (reportedly the reason that there was never a G5 laptop).

Look further down on the topic page for the September 13 post 'acceptable temperature for G5 iMac'. There is a discussion on the issues of lowering temperatures and an interesting link to Imac temperature issues. Also search this forum for 'heat' and 'temperature' and you'll find several discussions with tips for getting temperatures under control.

To those who claim that these operating temps are 'normal', I'd like to know where Apple or anyone else has published a bulletin of acceptable operating temps for the iMac G5. I'd also direct your attention to the high number (in the last 50 or so posts) of drive failures, fan noise problems, freezes, startup issues and dead power supplies - hardly what I'd refer to as normal.

Good luck, Robert.

Answer 3

Klaus1

Level 9

53,015 points

Sep 15, 2007 2:28 AM in response to RRack

My G5 iMac (see below) runs at a steady CPU temperature of 50-55 degrees C.

(Sorry, can't work in fahrenheit!)

Answer 4

MGW

Level 7

27,083 points

Sep 15, 2007 6:33 AM in response to Klaus1

55C is 131 Farenheit which is a normal number. However, temperatures in the 140 - 150 range when the machine is working are perfectly acceptable. Do not allow yourself to be scaremongered into messing about with the interior of your Mac, your temps are normal and don't worry about them!

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Answer 5

Bosco45

Level 1

15 points

Sep 15, 2007 7:33 AM in response to MGW

Let's recap:

a.) The component failure rate for the iMac G5 PPC is far higher than the G5 PPC towers. We can see this by scrolling thru the posts on this board.

b.) The operating temperatures in the G5 PPC are far higher than than the G5 PPC towers.

c.) The processor and hard drives are the same components.

Can we assume that there may be some connection between the component failure rate and the internal temperature of the iMac G5?

My recommendation that users do what they can to reduce temperature is hardly scaremongering; it's good advice.

For those of you who are concerned, search this forum for posts about temperature and you'll find a few tidbits about lowering them. You can also google 'imac G5 temperature' and you'll get a broader picture of this problem on some of the Mac user sites.

Good luck.

Answer 6

MGW

Level 7

27,083 points

Sep 15, 2007 7:54 AM in response to RRack

Robert - Some Rev A computers have had thermal problems, the vast majority have not. As long as your computer is operating normally and the fans kick in at appropriate times, I would leave everything alone and enjoy using it without paying attention to alarmist warnings.

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Answer 7

Bosco45

Level 1

15 points

Sep 15, 2007 7:04 PM in response to MGW

<<Some Rev A computers have had thermal problems, the vast majority have not.>>

Says who? where are the facts and figures to back up your pronouncements? What constitutes a 'vast' majority?

FYI: the Rev A had CAPICATOR issues; both the Rev A and Rev B use the same processor and have about the same operation temps.

The only survey I've seen is from Macintouch that found a 31% initial failure rate for the Rev A 20"G5 - later versions dropped to 11%-12%.

(www.popularmechanics.com/technology/upgrade/1707756.html).

I know of no other published figures for iMac component failures; if you're in possession of some that validate your 'vast majority' statement, please enlighten us.

You've referred to my advice here as 'alarmist' and 'fear-mongering'; I'd suggest that if you're going to be the self-appointed expert on these issues, you should actually espouse something besides your own opinions, i.e. some facts and figures.

Despite your pronouncements to the contrary, these things run hotter than other Macs and appear to have eleveted failure issues because of it.

Anything the user can do to reduce temperature will increase their lifespan.

Thank you.

Answer 8

RRack Author

Level 1

7 points

Sep 25, 2007 6:08 PM in response to MGW

Well...I'm well aware of Apple and their history with temperature problems. I've tricked out my dual 1.25 MDD to finally brought it down to safe steady temps. I am also not convinced that this is "normal". There are thousands that have had overheating failures. This is part of the reason of the caps exploding or leaking...heat. I've read hundreds of postings all over the web. In fact, the two that I have both had the hard drives replaced due to failures. What kind of odds is that? Both have had the boards replaced and one still needs the PSU replaced. It still needs to "warm up" before it will stay running. However, it's operating temps are a little lower and tolerable. This one in question: idle the thing is sitting at 60-65 C. The kiddo is playing some Nick Jr. flash games and it is spiking up to 83C. This still seems far too hot. Not to mention that the hard drive is cooking at about 55C. I thought I had helped the problem when I cleaned the heat sink and fans out. Then I had to reinstall OSX last night. Now I'm back up to these ridiculous temps. The thing is cooking just sitting there doing nothing. Both top fans are completely clean and screaming. I shouldn't have to slow the processor down to cool it. I've installed Temperature Monitor and keep setting the alarms higher and higher. It's now constantly going off and set at 80C. I'll do some more research and read some of those tips. I really don't want to spend more for yet another hard drive. I'm thinking that iMacs aren't as great as I once thought they were...

Answer 9

MGW

Level 7

27,083 points

Sep 25, 2007 6:20 PM in response to RRack

If your fans are screaming and your temps are as high as they are, call Apple and see what they can do for you. I assume you have the processor set to Automatic?

User uploaded file

Answer 10

RRack Author

Level 1

7 points

Oct 18, 2007 1:46 PM in response to RRack

Well...Apple won't touch it. The tech said that the temps are far too hot. However, they couldn't do anything to it because it already has a revised motherboard and PSU and other than being hot it's running fine. Well, I know that he really meant running fine for now. He did tell me me that it's probably due to the misapplication of thermal paste around and under the main logic board...Now I'm trying to find some or any information on where to apply the compound...I've got three tubes of silver waiting to be applied. Just need a little idea of where it should be before I tear it apart. I did some reading about the thermal pad on the G5 and that some people have removed this and replaced with thermal compound. Is this worth it to do while I'm in there? Just a side note...I also found a tiny rectangle silver magnet with double sided tape on it stuck to the inside back of the case. No idea why. Is this an accident or did it fall out of place somewheres? Oh btw...right now it's 68C. I converted some mpegs to mp4s last night and it was hovering around 85C.

Thanks much,
Robert

Answer 11

PJB

Level 2

365 points

Oct 21, 2007 5:11 AM in response to RRack

I wouldn't be too concerned about your computer's operating temperature unless it is misbehaving (shut downs, kernel panics, component failure).

There are a few thiings you can do if you think the computer is hotter than usual:

Firstly, you could make sure the processor performance is set to "automatic" in the energy saver preference pane. Secondly, you could make sure the computer case is clean from dust / other gunk. You can also reset the SMU - I think this involves removing the back cover on your iMac - check the documentation.

I've been using my iMac for about half an hour and the CPU temperature is about 45 degrees C and the hard disk about 36 degrees C, but slowly rising. The ambient temperature is about 18 degrees C.

For the record, I'm on my third G5 motherboard!

Answer 12

MGW

Level 7

27,083 points

Oct 21, 2007 6:33 AM in response to RRack

If it's still running hot, call Apple and tell them that it still isn't working properly. The fact that you have a replaced motherboard is only more reason to check it out, replacement have been known to be faulty, and you may be having other thermal problems that contribute to motherboard failures.

User uploaded file

Answer 13

RRack Author

Level 1

7 points

Oct 21, 2007 7:47 AM in response to PJB

So if i understand you correctly...don't do anything until it burns something else up? That makes no sense. Why not be proactive and fix the problem. I already know that this thing is poorly designed, overheating and destroying hard drives. I'm going to try and figure out exactly where the thermal paste is supposed to be and replace the thermal pad on the processor with silver compound...since Apple won't do it.

Answer 14

PJB

Level 2

365 points

Oct 21, 2007 5:01 PM in response to RRack

"He did tell me me that it's probably due to the misapplication of thermal paste around and under the main logic board."

In other words, neither you nor the tech have seen the CPU. Therefore what you are suggesting is pure speculation - thermal paste may or may not be the problem. Equally, how do you know it will burn something up? To get a new motherboard, I complained that the computer was noisy - nothing caught fire / died / packed its suitcase for Hawaii.

I was suggesting that you try to eliminate possible other causes - and as you computer is still working, if you start poking around inside you really do risk burning something up.

It seem like you have already made up your mind. Let's hope the paste fixes your problem.

Answer 15

RRack Author

Level 1

7 points

Oct 21, 2007 6:26 PM in response to PJB

I'm not really sure what you are getting at... Speculation is part of troubleshooting. I haven't pulled the sink nor the board as of yet...but if the fans are moving air and the heat sink is clean it should be running cool like the other identical iMac I have sitting right next to it. This thing is on it's second logic board and second hard drive. When the hard drive temperature is constantly exceeding the manufacturers limits the life is guaranteed to be cut short. By cut short, I'm talking about less than a year. Have any idea how much a 320gb SATA runs? I have an electrical engineering background and I know heat will kill electronics. I have completely rebuilt PCs, Macs, iPods and pretty much anything else that can power up. Anything that runs this hot will not last. I really don't care what Apple or anyone else says are suitable temp specs. That's how I know it will burn something up...because it already has!

The main cause is a poor case design and a hot running G5. Combine the two and you've got a toaster oven. I have eliminated all other causes...new PSU, new board (2nd), completely cleaned out heat sink and fans...All this and no change. It's sitting in the other room right now rendering a movie at a constant 190F! The hard drive is 140F. If i remember the limit for the drive is about 120F ish. I shut it down before the drive quits on me. What else is there to rule out? What would you suggest?