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New Mac Pro - Brief fan noise on start-up

Mhaddy

Mhaddy

macrumors 6502
Original poster
Oct 26, 2005
445
1
Canada
Well, after a disappointing diagnosis on my old PMG5 and thoughts on a refurb, I finally decided to buy a new one. A stock 2.8 8-core config for $2699 with my EDU discount along with an 8GB Touch, which after rebate and resale of the Touch, actually works out to be $34 cheaper than the $2499 refurb I was looking at.

Anyhow, picked up my new powerhouse last night and got things set up. However, I'm noticing a brief (2-3 second) "high rpm" fan noise on start-up, immediately after pressing the power button. It doesn't sound like it's out of control nor does it sound like the old full-blast fan noise that I experienced on my old PMG5. It just sounds like one of the case fans starting up and setting itself or something (it's hard to describe a sound!). Is this normal and has anyone else experienced this with theirs? Given how much my new purchase was, I want to ensure that it's perfect before going past those important first 14 days.
 
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mine has done that since I got it almost 2 years ago so I'd say it was normal
 
Yes indeed its normal (same on most PC's as well)

Its the video card running its fan at 100%. This is the default speed. Once the BIOS (or in our Mac Pro's EFI) gets up and running it sends the correct signal to slow the fan to a sensible speed (you should notice it speed up again when doing anything heavy 3D (Games)).
 
Yeah, it's normal, the fan always spins up quickly and then slows down once the computer has been on for a few seconds. Nothing to be concerned about. :)
 
Thanks for the reassurance. Are there any typical problems or quirks that I should look for in these first two weeks?
 
Mhaddy said:
Thanks for the reassurance. Are there any typical problems or quircks that I should look for in these first two weeks?
Click to expand...

Check disk permissions just to see if theres any underlying plist faults, run the code that forces your CPU's to 100% usage (sorry I can't remember it) and install either SMC Fan Control or iStat Menu Bar to monitor heat :)
 
^ run an extended hardware test from the first install DVD by holding D on startup.

just sleep your Mac Pro so youll never have to hear the fan noise again (except when you have to reboot after some updates). Mac OS X is stable enough to do this.

Schtumple said:
… run the code that forces your CPU's to 100% usage …
Click to expand...

Code: 
Yes > /dev/null & Yes > /dev/null & Yes > /dev/null & Yes > /dev/null & Yes > /dev/null & Yes > /dev/null & Yes > /dev/null & Yes > /dev/null

x8 becuase there are 8 cores in a dual CPU Mac Pro.

then to terminate all 8 "Yes" processes press "control+C" and enter

Code: 
killall Yes
 

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Thanks guys. Just so I'm clear, the tests that Schtumple and richthomas are suggesting are two separate tests? I've run the Yes > /dev/null test a couple of times on my Macbook Air (to show core shutdown) and this test is to confirm that the cores are OK? Kind of like a burn-in/stress test? Also, by doing this, am I explicitly voiding the warranty or anything of that nature?

run an extended hardware test from the first install DVD by holding D on startup. Does this just perform an overall diagnosis versus a stress test as above?
 
Mhaddy said:
Thanks guys. Just so I'm clear, the tests that Schtumple and richthomas are suggesting are two separate tests? I've run the Yes > /dev/null test a couple of times on my Macbook Air (to show core shutdown) and this test is to confirm that the cores are OK? Kind of like a burn-in/stress test? Also, by doing this, am I explicitly voiding the warranty or anything of that nature?

run an extended hardware test from the first install DVD by holding D on startup. Does this just perform an overall diagnosis versus a stress test as above?
Click to expand...

its the same test. Your MacBook Air is dual core so if you ran "Yes > /dev/null & Yes > /dev/null" and saw no problems then your MacBook Air's CPU is fine. it basically just writes junk data to /dev/null utilising a whole core, so it can be seen as a CPU core stress test.

you are not voiding the warranty of your Mac. its basically the same as fully loading your CPU's cores to encode video, but its just easier.

the hardware test only test your Mac's hardware like RAM, Logic Board etc.
 
richthomas said:
just sleep your Mac Pro so youll never have to hear the fan noise again
Click to expand...
Just tested this last night -- it still makes the same fan noise waking from sleep. Now that I know it's normal, it doesn't bother me, just FYI.

richthomas said:
its the same test. Your MacBook Air is dual core so if you ran "Yes > /dev/null & Yes > /dev/null" and saw no problems then your MacBook Air's CPU is fine. it basically just writes junk data to /dev/null utilising a whole core, so it can be seen as a CPU core stress test.

you are not voiding the warranty of your Mac. its basically the same as fully loading your CPU's cores to encode video, but its just easier.

the hardware test only test your Mac's hardware like RAM, Logic Board etc.
Click to expand...
Unfortunately when I run the dev/null test on my Macbook Air, I get both cores dropping to 800MHz and the unbarable lag that was evident before the "fix" issued by Apple. This time instead of one core cutting out and the other going to 100%, both just drop to 50%. But that's a thread for another story, heh. But now that I have my Mac Pro, I can actually do something about my Macbook Air. I'm going to to do a clean install with 10.5.5 and see if that changes anything (I've read on this forum some users reporting success doing a fresh install) and if that doesn't work, it'll be another trip to the Genius bar or call to Apple Support.

Thanks for the insight -- you've been very helpful!
 
Yep, it's normal. My baby [specs in signature] has done that since day one- I think it has something to do with the start of the PSU- and that initial startup jolt it surges through the computer. Not sure though, I'm no technician. :D
 
Fan Noise

When I restart my Mac Pro - or start it for the first time, the fans spin up briefly. There is nothing wrong with your Mac Pro - as others have pointed out, this is normal! During startup and reboot, there is a breif period where the Mac Pro's firmware cannot monitor temperatures and adjust the fan speed - so they go to full. Here's why:

There are several fans in your Mac Pro - they cool the processor, the power supply and the memory. Additionally, a fan is affixed to the graphics card's to cool the GPU. They are all thermally regulated - if things get too hot, the firmware tells the fans to spin faster to cool things down. During reboot or initial boot, in the absence of firmware to regulate the fans, they are set to go to max speed - this is to protect the CPU and GPU from heat damage. Once the firmware comes (back) online, the fans are regulated to normal speeds.

Here is what this sounds like on the Mac Pro: http://s190.photobucket.com/albums/z260/kmkr03/video/?action=view&current=macpro.flv

Lumpy
 
All right, I ran the Yes > /dev/null test on all 8 cores and let it run ~10-15 mins. My CPU A and CPU B temperatures ran up to 150F/66C before I started to become uncomfortable and killed the test. Is this normal?

I also couldn't get the diagnostic test to work -- I put the Install DVD in, restarted and held "D" down... OS X just booted normally. Thoughts?

Edit: Just got off the phone with Apple Tech Support and they confirmed that the "upper limit" of the Mac Pro CPU temperature range is 170-180F, so it looks as though I was still within safe limits. I will run the test again and see just how hot it gets and proceed from there.
 
Uhm, guys, my mac pro never had that startup sound (the mac beep). Is that a bad thing? :confused:
 
Well, I ran the test again and managed to get the temperatures of both CPU's up to about 164F where it eventually peaked and would fluctuate up and down to 158F or so. I didn't hit that 170-180F mark that Apple Tech Support mentioned, so I'm happy. :)

Volante, what mac beep are you talking about? The fan noise or the start-up chime?
 
Mhaddy said:
Well, after a disappointing diagnosis on my old PMG5 and thoughts on a refurb, I finally decided to buy a new one. A stock 2.8 8-core config for $2699 with my EDU discount along with an 8GB Touch, which after rebate and resale of the Touch, actually works out to be $34 cheaper than the $2499 refurb I was looking at.

Anyhow, picked up my new powerhouse last night and got things set up. However, I'm noticing a brief (2-3 second) "high rpm" fan noise on start-up, immediately after pressing the power button. It doesn't sound like it's out of control nor does it sound like the old full-blast fan noise that I experienced on my old PMG5. It just sounds like one of the case fans starting up and setting itself or something (it's hard to describe a sound!). Is this normal and has anyone else experienced this with theirs? Given how much my new purchase was, I want to ensure that it's perfect before going past those important first 14 days.
Click to expand...

mine does that too :) i asked that when i first got my mac pro and it's normal.
 
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