With one click, Spencer Critchley just eliminated the nail-dragging squeak my dual-G5 used to make every time it ran a complex screen saver or iTunes visualizer. His tip was to disable processor napping.
Click once, squeaks vanish. Disabling processor napping on my dual G5 eliminated the squeaking sounds it made when running complex visuals. But could there be any drawbacks?
There’s some speculation that disabling napping boosts power consumption and shortens processor life, but I haven’t found any data on how much, if any. One interesting thread noted:
With Nap enabled the fans idle at 550 rpm in lowest CPU setting but they go up to 2,000 rpm when you scroll in Safari or do anything to use the processor.
With Nap disabled the fans idle at 1,400 rpm at highest CPU setting but they never go up or down from there.
I find that with nap disabled the 1,400 rpm is not very loud and I stop noticing it. With Nap enabled it’s quiet for like a few minutes then I hear the fans rev up and down, up and down. It’s so annoying I turned it back off.
I agree that a constant fan noise would be easier to deal with than the unpredictable wheezing and resting. I often use BIAS SoundSoap to clean up recordings, which requires first taking a noise fingerprint. If the background noise changes over the duration of the recording, that becomes difficult.
Staying Awake
An entry on the Digidesign User Conference site notes that the Mac will revert to Nap state when rebooted. It links to a downlodable script to re-disable napping after every restart, but the script seems to be written backwards. I modified it to the following, saved it as an application, and set it to run as a log-in item.
do shell script "hwprefs cpu_nap=0"Have you had similar results? Do Intel Macs squeak as well? And how do you overcome the friggin’ fan noise? I’m getting close to buying a padded enclosure. (If not for my Mac, for myself!)
Neat. I'm going to try this for a couple of days with my iMac G5 (Rev A).
Ouch, cancel that! Fan noise is nearly at its maximum when I turn off napping with my iMac. Pity!
Try this: disable nap then disable CPU 2. Then re-enable nap and re-enable CPU2. It works - don't ask me why.
@Rob: For what it's worth, my fan's running pretty quiet now.
Thanks for all the additional tips, David! Speaking of padded enclosures, I use a Raxxess Isoraxx to house the Mac and several drives. It works fairly well. It uses quiet, variable-speed fans, which generate quite a lot less noise than all those components would unhoused. In the past I've used custom-built enclosures that exhaust their fans into a neighboring room or to the outside. That approach is quieter still, but of course makes for a bigger (and potentially riskier) project.
As an answer to your embedded questions:
As far as I can tell, no, intel macs do not "squeal" :)
At least I haven't heard any from MacPro's MacBook's or MacBook Pro's YMMV.
@Anonymous: Thanks. My G5 doesn’t squeal anymore either. ;-) Still, for recording, I’ll probably continue to use a long mic cord.
Check you processor temp when disabling Nap. I found mine sky-rocketed seconds after disabling it.
Help! After upgrading to Tiger, I no longer have a tool to turn off napping! no hwprefs in CHUD 4.4.4! The chirping is back worse than ever? Any other version work with Tiger? I'm dead in the water until I fix it again. Any suggestions?
Always, enable the 'Allow Nap' processor because it reduces the power consumption and heat, there will not be any adverse effects, but your mac may run warmer and consume more power.If you disable the processor, it shortens your CPU's life because of the heat and constant strain.