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TiffanyBee

macrumors member
Original poster
Apr 30, 2010
45
0
California
I wish I had something to record how ridiculously loud my fan is roaring right now.

It's not that little purr you hear when you're playing games, it's roaring.

Non-stop. My game crashed on me when I was playing 3 days ago. My computer got super hot. I'm going to call the Apple ASAP. Has anyone else experienced this problem?
 
I was playing The Sims 3. haha. But that's not the point, my fan started roaring when I was watching Bones (tv show) online.

At first I thought it was just part of the show or something & when I muted it..it was my fan.

I called Apple & the guy thought the sound was a loud AC or a ceiling fan but I told him it was my iMac.

This is my second iMac. My first one was replaced because I experienced a high pitched whistling noise that was correlated with the screen's brightness. My current iMac still has that problem but now it's got an out of control loud fan.
 
Fan Roaring may = runaway processor

Some time ago I noticed my MINI was getting noisy and warm. I had iSTAT installed as a widget to the Dashboard, and i opened it and noticed (in the right hand column) a 94% usage by a processor (it had "av" in the name). That seemed excessive.

A friend suggested the following solution (having iSTAT is not essential to doing this; just do it when the fan roars)

"Just launch Activity Monitor (in your /Applications/Utilities folder), select all processes from the pull-down menu, and then click on the column header to sort by CPU usage. This will tell you what application is the culprit. If it's not a critical application, use Activity Monitor to quit or force quit the offending process."

I did that and nothing adverse happened, but the fan quieted down and the iSTAT display no longer showed the high usage.

Hope this helps.
 
Interesting... I've had my G5 iMac go to ridiculous fan speeds about 10 times now. It sounds like a full-sized vacuum cleaner when it does this, no lie.

There's no load on the iMac when this happens. I've had it happen in winter and summer (ambient temps not a factor either).

First time it happened it scared the #*&#(& out of me from 2 rooms away. The first few times it happened, I panic'd and shut it down, thinking it was on the verge of melting down or something. Then I watched the next time, looked at console logs, no high temp, nothing in the console, nada. The fans spooled down to normal after about a minute or so.

So, back to the OP, yes, I've had this happen, but no clue as to why it starts and why it stops.
 
I shut down my computer, called a representative & he told me to hold down alt + command + r + t when I start up my iMac but that did diddly squat.

Like you said, my iMac sounds like a vacuum cleaner. It wasn't hot, no programs were running, it just pushed air out constantly. No lag or anything but I thought my iMac was going to explode as well..

I used Time Machine to back up my files & the fan was still going. It's a permanent roaring..definitely not going to stop any time soon as it was like that for 30-40 minutes straight so I just turned it off.

Guess we'll see what the problem is on Friday when I take it in.
 
when the fan is going open Activity Monitor to see if some background process is eating away at your CPU. you can also check the logs in Console to see if there's any repeating error messages.
 
take it as you want, but
mac's cooling system is the worst
out there.

Every after Market CPU or VGA cooller
is better than macs. I have an i5 750
desktop PC (hackintosh) and under heavy
load with Prime or Lynx the max temp of the
CPU is 49 degree Celsius - which never happens
with games or programms. By that I mean
my temps are around 46 at max.

I use Noctua U12P cooller.

Really, buy a desktop for games. I killed two alu Macbook Pro playing Left4Dead. Macs are crappy, but you just want to have them!
 
^ Okay that did not contribute to the resolution of my problem at all but thanks for your input...

My fan actually stopped roaring after I left my Mac off for two days. Then I took it into the Apple store. They ran a diagnostics test & said nothing was wrong with it.

Now it's roaring again & it has been for 2 weeks. I left it off for an entire day & it still roars. It's still going haywire & my CPU fan is going off at 4000+ RPM. I don't know if I have a faulty CPU or if the sensors are defected.
 
harddrive upgrade

you didnt by any chance upgrade the harddrive yourself of by a local dealer did you? the heat sensors are no long on the harddrive but in it and each brand of drive uses a different connector (god knows why) so if the temperature is not read right by the mac the full fans kick in as it cant get a correct reading from the harddrive, basically if u replace harddrive in the new imacs it has to be a model like for like ie seagate for a seagate, samsung for a samsung.
 
Nope. This is my SECOND iMac. I have not opened it up nor have I done anything to it.

My first iMac had that annoying whistling sound & this one still has it but it's less noticeable (I guess I forget that it's even there).

Right now, my fan is roaring again. It seems to do this after I watch videos including youtube videos....or just after a short while when I had Photoshop running. But even last night, it didn't go off & I had Photoshop running the entire time.

I'm definitely hoping to get a replacement soon.

Northbridge is 148 degrees Fahrenheit & GPU diode is 140 as well. CPU fan is going off at 4000 rpm
 
I took my iMac to the Apple store & they ran a diagnostics test. My heat sensor was off so that was the problem.

They gave me a replacement & it's perfect so far. It doesn't even have that high pitched noise that is associated with screen brightness!
 
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