Mac OS X 10.4: "Beeping" or "Chirping" noise back for some G5s

Some PowerMac G5s exhibit a "beeping" or "chirping" noise under heavy processor loads after being upgraded to Mac OS X 10.4 (Tiger).

We previously reported this issue in December of 2003, but there has been a dramatic re-emergence of the problem since the release of Mac OS X 10.4. Several users have cited the new PowerMac G5s introduced in late April as exhibiting this problem, though the correlation is likely based on the fact that these are the first G5s to ship with Mac OS X 10.4 installed.

Setting processor performance to "Automatic" or "Reduced" rather than "Highest" in the Energy Saver pane of System Preferences seems to eliminate the noise for some users, though obviously a noticeable performance penalty becomes apparent in some applications.

MacFixIt reader Frans van der Geest writes:

"After a install of OS X 10.4, I noticed a 'Chirp sound' when scrolling a document on my Dual 2 GHz G5. Setting the Energy Saver option for processor speed to 'Automatic' and the chirp is gone. Setting it to 'High' and its back again. This did not happen in Mac OS X 10.3.9 when scrolling."

Another solution that was successful when this issue appeared in 2003 involves using Apple's CHUD tools and disabling the "Nap" feature.

This is accomplished by first downloading and installing the Apple CHUD tools, restarting, then using the newly available "Processor" pane of System Preferences to disable CPU Nap.

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