From inception 2009 Mac Pro family computers had a significant bug: with any use of audio* they suffer as much as 26% performance degradation, consume excessive power, and generate large amounts of heat.

This site collects bug information, diagnostics, remedy and data relevant for users.

For almost a year Apple had been mute about this bug despite many efforts to bring it to their attention. At last, a bug fix is available: HT4034 for Snow Leopard only.

Audio patch 1 introduced new problems in Firewire audio, this is now fixed in Mac Pro Audio Update 1.1 (3rd May 2010).

However the last audio fix introduced another bug:
after waking the compurter from sleep, the sound output channel is switched (the side effect is that keyboard volume controls appear to not work). This has to be re-set using the sound interface in the System Preferences.

HT4034 problems include:

• Under the bug fix (under SL) there is a new bug in many firewire audio interfaces [1].
• There is no fix for MacOS 10.5 (Leopard) [2].
• Fan response (SMC) seems poor under heavy load [3].

User participation is in conjunction with the Facebook page 2009 Mac Pro audio/firewire/power bug. See Links for further contact and community information.

[1] The bug fix produces a "high pitched whistle of slightly oscillating frequency" with Apogee, Presonus Firebox, RME Fireface800 and M-AUDIO ProFire 610 , MOTU 896mk3 Firewire audio interfaces. See Links.

[2] Users have tried adding the bug fix kext files by hand to 10.5.8 but without success. Some users have to use Leopard (cannot use Snow Leopard).

[3] Some users are still experience very high temperatures under heavy load, so use fan speed boosting extensions (see Remedies).