Mac Pro Fans run extremely high!

Open Activity Monitor in the Utilities folder. Select All Processes from the Processes dropdown menu. Click twice on the CPU% column header to display in descending order. If you find a process using a large amount of CPU time (>=70,) then select the process and click on the Quit icon in the toolbar. Click on the Force Quit button to kill the process. See if that helps. Be sure to note the name of the runaway process so you can track down the cause of the problem.

Fir better detailed accurate thermal sensor read install Temperature Monitor

SmcfanControl sets the lowest rpm and users creste multiple profile settings

900 - 1200 - 1500 - etc and change as needed and test to keep system and cpu at 'reasonable temps'

Not sure how to get GTX readings, and may not be any OS X utility to monitor let alone control

You need OEM DVD to use AHT

CPU of course lower temp is better but you can expect to see 65ºC - and avoid or stay below 80's at all costs.

Use the two apps in conjunction.

Those are minimum fan rpm so if you know you will be stressing system, it is easier to switch to "ultra" set first and watch, and even 2000 rmp won't do any harm except to being loud.

Hardware Monitor is paid and can track temps, has more sensor readings and alert if X hits Y which might be handy.

Do you have Apple Care? You should have the Apple Techs look at it. Those fan speeds are outrageous. Especially if they speed up like that randomly.

My Mac Pro fans (2009 4,1) never, ever reach speeds like that. When I stress the CPU and max all cores, the fans hardly budge from their minimums. I've never seen the BOOST higher than 1300 rpms.

So I have the opposite problem---not enough RPMs.

Apple might give you a new logic board if they can't fix the SMC.

beauleland wrote:

I realize the graphics card will heat things up a bit, but this still seems abnormal. Can anybody help me troubleshoot? Or at least provide an explanation of the fan layout of the Mac Pro, or list some recommended fan speeds? I just can't seem to figure this thing out.

Thank you so much.

It does look abnormal, especially if Activity Monitor doesn't show any processes using much of the CPU's capability. Keep in mind that going full blast, your CPU can show up to 1,200% usage in Activity Monitor (six cores, two threads each).

First, we both have the same Mac Pro with the same amount of RAM. Based on Temperature Gauge (from the App Store), the intended minimum and maximum speeds for the fans are PCI - 750/4500, PS - 750/2800, Exhaust 750/2800, Intake 600/2800, BOOSTA 800/4000.

Working up, the Intake fan is at the bottom of the front grill. The Exhaust fan is at the back end at the same level. You've had the processor tray out. Inside the processor block (the box behind the DIMM slots with horizontal fins) is BOOSTA. There'd be a BOOSTB if you had two CPU's. Those three (or four) fans cool the CPU and RAM. Above all that is the PCI fan, which is set in a bit from the grill and, for some reason, doesn't fill it's space at the front so, theoretically, the air could blow into the PCIe area, make a U turn around the right side and go back through the fan again. 😕 Finally, behind the optical drive bay is the PS and the fan is at the front of the PS. There's also a fan on the video card, and I've never seen a monitor which could show that fan's speed or temperature.

I keep an eye on smcFanControl's temperature reading in the menu bar and when it heads north of 100ºF I start going to one of the higher fan speed settings I've established. That's probably being over-cautious but I like my Mac Pro. And if the fans can't do the job, it's time to blow the dust out, and that includes the dust inside the video card.

Hope that helps some.

Whenever wacky things related to the SMC happen, and SMC Reset is in order:

Intel-based Macs: Resetting the System Management Controller (SMC)

If you have only 1 month of warranty remaining, then you really should take it to Apple. I might be a pain to do that, but it may be worthwhile if they can repair it.

You should first attempt the SMC reset. Some suggest holding down the power button for 10-15 seconds while the machine is unplugged. It's worth trying.

If the problem continues, then do make use of your Apple Care. Just let them run the Hardware Test or Service Diagnostics. I've no idea how you could fix something like this on your own (if SMC reset fails to work).

That's amazing that you never allow your system to exceed 100F. My CPU idles at 106F. There is never a moment when my system isn't North of 100F.

It nearly reaches 100C under load. Why Apple allows this I've no idea. But it is quiet.

Studio K wrote:

That's amazing that you never allow your system to exceed 100F. My CPU idles at 106F. There is never a moment when my system isn't North of 100F...

Well, sometimes it gets up to 104ºF and that's when I start boosting the fans.

...It nearly reaches 100C under load. Why Apple allows this I've no idea. But it is quiet.

I think you've answered your own question. Read through the threads complaining about fan noise vs complaining about heat. It seems like there's a lot more of the former.

Can you imagine if there was a fan in the iPad?😉