Possibly eliminate 'chirping' sounds from G5 CPUs

Nov 07, '05 05:37:00AM

Contributed by: robg

If you've silenced your G5's fans, but your G5 still makes occasional odd noises -- quiet chirps and clicks -- then this hint might help. On my Dual 2.0 G5, I would hear these chirps and clicks on occasion, and couldn't ever tie them to anything the machine was doing. After doing some digging, I found a solution that worked for me, so I thought I'd share it here.

The solution to this chirping problem is to disable "CPU napping." From my understanding of it, this is a lower-power mode for the CPUs, invoked automatically by the G5's power management functions. But how does one do that, you may ask? You need to install CHUD, which is short for Computer Hardware Understanding Tools. It's linked on this page at Apple, and I think you get them automatically with Xcode (though I may be wrong). After installation, look in the Other section of System Preferences, and you'll see a new Processor panel (I think it's called Hardware in 10.3). Open that, and uncheck Allow Nap.

For me, that was the end of the chirps -- perhaps at the expense of a shorter CPU lifetime, but I'll take that risk for the silence gained. Also note that if you restart, the nap setting is reset (at least, mine is), so you'll need to re-open the prefs panel to fix it again. Alternatively, this older hint explained how to use a simple AppleScript to enable the nap setting at each restart. Change the =1 to =0 in the script, and you should have a "nap disabling" startup item (though I haven't tested this).

If you've got excessive G5 fan noise under 10.4.3, also see this hint.

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