G5 Dual 1.8 GHz fans gradually go to full speed and stay there

My G5 Dual 1.8 GHz boots normally and quietly, with no freezes or panics. However, within a minute or so, I hear the fans begin to gradually gain speed. This continues for a couple of minutes until the fans reach maximum speed, making my room sound like a wind tunnel. This occurs with no programs running, just sitting idle at the Finder desktop.
I've checked the CPU & system temperatures using the shareware utility "Temperature Monitor 2.5" and everything is running cool, barely above room ambient, so there is no thermal reason for the fans to "take-off" like this as the heat pipes are doing their jobs to cool the CPUs.
There is no restriction on air flow around the case, and the acrylic side panel is installed. Interestingly, removing the side panel seems to have no effect on fan speed, whether installed or not ... maybe it's just the liquid cooled G5s, but isn't removing the side panel suppose to force the fans to full speed?
I was wondering if this out of control fan speed is a known issue that can be resolved with either a firmware update or software patch? Does this indicate the need for a thermal recalibration?

I've since answered my own question on this ... The reseller had installed OSX 10.3.2 as the boot OS. The (Late 2004) DP 1.8 GHz G5 requires 10.3.5 minimum, and with that update, the problem went away. The G5 now runs quietly.
This was far simpler than I had expected. Thanks.

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I have a dual 1.8 ghz pwer pc g5 and sometimes i put it in sleep mode and come home on my lunch break and the fan is running at full speed and the computer has frozen up...what is going on here?

and sometimes i put it in sleep mode and come home on my lunch break and the fan is running at full speed and the computer has frozen up...what is going on here? is it a virus or has my computer been hijacked? it cant be good for the computer...anyone ever had this problem..?

Your problem has been reported many times, but causes are as varied as individuals.
Can we assume that a hard shutdown allows a normal restart?
Can I assume that you have used Disk Utility from your OS X install disc to repair the hard drive directory? The freezes and hard shutdowns require that the drive be repaired (not permissions) or soon the machine won't boot at all.
If the root issue is software related, in Console (the application) under Logs, there should be loggings around the time of sleep and logs that tell you what process went wild and froze the machine.
Network activity is also a common casue.
Other info:
http://support.apple.com/kb/ht1776
If hardware related, such as an external drive, other USB device (Wacom tablet) or USB PCI card, ejecting, disconnecting, removing, or in the case of the Wacom, updating drivers, are all potential remedies.

Fans are running at full speed after hard drive upgrade. Used same brand drive.

My Western Digital 500GB hard drive crashed. The date on it is Aug. 2010. I swapped it out for a Western Digital Caviar Black 1TB. All plugs were identical including the temp sensor cable. My fans now run at full speed. What gives? BTW. This is th 3rd WD hard drive to fail at my office in multiple iMacs. I have a 21.5 iMac i3 3.06ghz. I have tried the SMC reset,.. no luck. Reset the PRAM,.. no luck. Hard drive and computer function perfectly, it just sounds like a loud annoying PC.

After a little more research the only thing I found for 21.5" mid 2010 imac were three part numbers for three sensor cables which are a function of vendor:
922-9215, Hitachi
922-9216, Seagate
922-9622, Western Digital
The strange thing here is these are vendor specific and not model within vendor specific. So you started with a WD drive and replaced it with different model, but still a WD drive. So you would think it would require the same sensor cable.
Maybe the drives are different enough for this to matter. Or maybe you should check the connections one more time. Be it model of drive or connections, whichever it is, the sensor cable is the source of your problem.

Fan running at full speed and all the time!

Hi,
I was wondering what could be the reason for my fan running on full speed at all times?
It is pretty annoying especially when I am in a quiet room. This just started happening this morning and I thought it was just going to stop but it didn't so I restarted my MacBook and shut it down also and still no luck.
Oh...
My battery meter only says 1:45 after I just took it off the charger when it said it was fully charged and I had the green light on my charger.
What could be the reasons for these two things?
Thanks,
Sam

I reset the PMU and the fan is still going at full blast right when the MacBook starts up.
Will I know that the PMU is reset or will it just fix the problem if it is?
Does anyone know a solution?
The computer is running fine but it's just the fan that is really loud and going at full speed and the battery life is extremely short for some reason.

TS1433 The fan of my 2013 iMac running 10.9.5 keeps running on full speed even if there is no programs running. SMC reset is not working

The fan of my 2013 iMac running 10.9.5 keeps running on full speed even if there is no programs running.
I've tried the SMC reset, but around 5 minutes after restarting the computer the fan picked up speed again.
When trying to shut down the mac normally and turning it back on - the fan starts directly.
Thanks already for any tipps or tricks to resolve this problem!
Additional Information:
2.7GHz Intel Core i5
8GB 1600MHz DDR3

Hi @krod619 ,
Thank you for visiting the HP Support Forums and Welcome. I have about your HP Pavilion dm4 3099se Notebook and overheating error and shutting down. I would reset the BIOS with this document selecting the reloading the BIOS default settings. This will reset the fan.
Hope this helps.
Thanks.
Please click “Accept as Solution ” if you feel my post solved your issue, it will help others find the solution.
Click the “Kudos, Thumbs Up" on the bottom to say “Thanks” for helping!

MY FAN IS ALWAYS ON FULL SPEED

Please help out there my MB fan is always on full speed especially when whatching ovies on Batt power which drains my batt quick. and i was not like that before

especially when whatching \[m?\]ovies on Batt power
First, movies are CPU-intensive tasks, which may explain the need for fan speed. That might not be all, though.
The thing to do it run /Applications/Utilities/Activity Monitor to see which processes are using the most CPU. It's entirely possible that you have some runaway process running that's causing the system to run hot, and therefore need additional cooling.

Fans go on at full speed 1 min. after computer goes to sleep

Problem: Fans go to full speed 1 min. after it goes to sleep-mode. The fans will stay on until it wakes up from sleep-mode.
Computer: Apple Power Mac G5 Dual 2.3, OS 10.4.9, 4.5 GB RAM. 2 HD, late 2005 version.
The problem happens every time I put it to sleep, even right after it has been turned on.
I have measured the CPU temp to be as low as 36-40C and it will still turn the fans on high speed when put to sleep.
I have reset the P-RAM and the SMU.
I have installed a fresh version of OS 10.4.9 on second drive, booted from it and it still turn the fans on 1 minute after it goes to sleep.
I have had all the RAM out beside the original RAM. I did an extended Apple Hardware test which passed.
...any ideas ?
-e
5 Macs in total Mac OS X (10.4.9)

After trying all that, it sounds like it's hardware-related--possible logic board--but try this yet.
Do an Open Firmware reset: Hold the CommandOption+OF keys during startup. At the '>' prompt type:
>reset-nvram
Return
>set-defaults
Return
>reset-all
Return
The reason the fans are taking off, is because the OS stops communicating with the logic board.
-Bmer
Mac Owners Support Group
Join Us @ MacOSG.com
iTunes: MacOSG Podcast
 An Apple User Group 

One of my MacBook Pro's fans is running at full speed

Out of the blue today, my 2011 MacBook Pro started fans went mental when I awoke if from it's sleep. They started running at full speed, far louder than I've ever heard them before. I searched through other discussions and it suggested I try an SMC reset. I performed one of these with no success.
I then opened smcFanControl and noticed that my leftside fan was running at 7000rpm+ and the rightside fan was running at normal speed 2000rpm. It randomly spools on and off high speed and I cannot find any fixes or similar problems online. Can anyone suggest a fix for this or should I be taking it to a repairer?
FYI my logic board was only replaced in April under warranty so could it be faulty?

Hi andyBall_uk
SMC fan control measures temp also. Currently running at 47*C as you can see in the screenshot below. I tried overriding the fan speeds...works for the right fan but not the left one so it appears only the left fan has the fault.
The weird thing is, when you press your finger down anywhere on the left speaker next to the built-in keyboard, the fan slows back down to normal speed, but when you let go it speeds back up again. I might open it up in the morning to see if any of the connections are loose, because it seems weird that this happens with a small amount of pressure applied to the body. Also of you tilt the macbook it sometimes slows back down to normal speed (but sometimes stays at high speed). I will let you know how I go. Thanks for your suggestion/s

2012 iMac fan sporadically running at full speed.

I purchased a 21" iMac in October. In the last two weeks, the fan has started having issues. It will intermittintely run at full speed for anywhere from 5 to 20 seconds, and then shut off, only to max out again in a minute or so. The computer itself is cool to the touch, the only programs running are Finder and Google Chrome, and it's in a well ventilated and cool area. I've already reset the SMC and the PRAM, seeing if either of those solved the issue, but it is still occuring. Anyone have any idea what might be causing this?

Could be a defective sensor. You can also try Intel-based Macs: Resetting the System Management Controller (SMC) and see if fixes it. If the computer is newly purchased, then take it to the Apple Store for repair. it's in warranty.

Fans running at full speed and slow iMac

I have a 2009 iMac that's used every day.
More and more frequently, the fans decide to go up to full speed. I've also noted my iMac is struggling somewhat this past year with standard tasks like iPhoto and iTunes. It even crashed yesterday when adding name tags to iPhoto.
After a reset the fans slowley go back to normal running speed.
I'm all backed-up in two separate locations, (JIC).
Any pointers on what I can look at?
Thanks
Ollie

Ollie ...
Your profile indicates your Mac has v10.5.7 installed. That's an outdated version of Leopard.
Click Software Update from your () menu top left in your screen.
Or, install the Mac OS X 10.5.8 Combo Update
Either way, restart your Mac after the updates are installed.
And how much free space on the startup disk?
Control click the MacintoshHD icon on your desktop then click Get Info.
You'll see Capacity & Available in the Get Info panel. Make sure there's at least 15% free disk space.
Run Disk Utility to verify and if necessary, repair the startup disk.
Launch Disk Utility located in HD > Applications > Utilities
Select the startup disk on the left then select the First Aid tab.
Click Verify Disk (not Verify Disk Permisions)
If repairs are necessary, help here > Using Disk Utility to verify or repair disks
More tips here > Mac troubleshooting: What to do when your computer is too slow | Macworld

PMG5 Dual 2.0 CPU Fans Running at (very) different speeds

I purchased a refurbished PowerMac G5 Dual 2.0 from Apple 8-10 months ago and I always thought the fans ran louder than I expected. Recently, I opened the case and noticed that the bottom front CPU fan was running much slower than the top CPU fan (with the clear shield in place). I checked this with software and here is what I found...
CPUA ~ 300 rpm on average
CPUB ~ 3150 rpm on average
CPUA Temp ~ Amb 46C
CPUB Temp ~ Amb 37C
Nothing changed when switching from Highest Performance to Automatic. Is there a sensor that needs fixing/cleaning or should I take it in for service?
Thank you for your help!
-Will
PowerMac G5 Dual 2.0 - GeForce FX 5200 Model Mac OS X (10.4.7)

Yes take it in, this is a considerable difference.
There is only a few hundred (at most) RPM difference between my CPU A and B intake fans.
Either you got a dead processor or your fans need to be recalibrated or your firmware isn't right.
All three cases is a good reason to have Apple look at it.
It might be the software your using to read the fan speeds, download Hardware Monitor, it seems to be the most accurate and up to date.
I'm sure you have stressed the processors and checked in Activity monitor to see if both your CPU's are alive and kicking.

I am running Xsan 2 with primary/backup meta controllers and both of my servers showing no link on the Fiber channel cards....have 2 G5 dual 2.3 GHz systems, 6 gig ram, 10.5OS. and PCI-X FC cards. QLogic 5600 switches. Looking for the non-obvious

They have been up and running for over a about a year on XSAN 2 and all of a sudden started having problems with data transter and then won's connect anymore
Thanks

Quote
amd 64=12a @12V
ati 9800=7.5~10.5a @12V (assuming 90~125 watts) a max load,
a 9600 ir nvida 5200 used far less power
so your already at 18a with no fan,s no hd, no cd,no dvd ,no mobo chipset , no mem, no sound..etc
If you exclude the motherboard, memory, etc like you did there, the amd 64 draws 7.2A @ 12V.
90~125W for an ATI 9800?! [irony]Are you working for a PSU manufacturer or what?[/irony] That's just absurd.
Go read this post to get a feel for the actual power consumption: https://forum-en.msi.com/index.php?postid=297061&sid=#post297061

Mac Pro fans blowing continuously at full speed.

Hi guys, just bought a Mac Pro off someone. 2006 model, 2.0 quad core.
The guy was running two x western digital 500GB drives. But took them out and replaced it with a seagte ST3500413AS 500gb drive (new).
Mac OSX installed fine. But when i boot it up the fans go crazy! and dont stop.
Did a heat montior test and all looked okay, i think it was 30-50 degrees for every component.
Used istat and the figures for the fans were as follows:
Figures show approx:
Power suply 599rpm
Exhaust 1547rpm
CPU fan 499rpm
HD expansion 2865rpm
Now obviously somethings wrong. I took the drive out and pushed it back in to make sure it made good contact, i have swapped bays etc, same problem.
Any ideas guys?

Launch the Activity Monitor application and select the CPU tab. Click the heading of the "% CPU" column in the process table to sort the entries by CPU usage. You may have to click it twice to get the highest value at the top. What is it, and what is the process? Also post the values for "% User," "% System," and "% Idle" at the bottom of the window.

Cooling fan just came on full speed

Freaked me out. Didn't know there was a cooling fan.
How do I get it to turn off?
It started up when I started a program. Restarting and shutdown doesn't make a difference.
There haven't been any recent updates described as "firmware". All recent SW updates have been applied.
Got a phone call the other day asking if I wanted to extend the warranty. I said "No". Hmm.

Dave
Welcome to Discussions
First try resetting your SMC!
Open this link for the instructions:
http://docs.info.apple.com/article.html?artnum=303446
Dennis
17" iMac Intel Core Duo 1.5GB Ram Mac OS X (10.4.8) Maxtor 300GB FireWire 2G Nano

Fans full speed and LCD temp sensor issue

Hi
So... Last week I replaced my internal iMac (mid 2010) HDD with an SSD. I knew that there would be the fan problem but I just shorted the HDD temp cable infact the HDD iMac runs on about 1000 rpm. The problem is that the CPU and Optical Drive fans run at about 4000 rpm! I googled my problem and I realized that those two fans are not related to the HDD temp sensor cable (RIGHT? ) . But when I removed the LCD panel of the iMac I accidentaly damaged the LCD temp sensor. So now I think that the CPU and OD fans are related to the LCD Temp Sensor.. Replacing it I should have all my problems solved.. Does it make sense? Thank you guys for your answers.
P.S. I resetted SMC and all the other stuff..!

Bring it in for service. If you feel you damaged a sensor, you could have damaged more. Best to have a trained eye make sure nothing else is bad.

G5 Dual 1.8 GHz fans gradually go to full speed and stay there

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