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Some of you might be interested in the topic I have raised at InsanelyMac regarding an Apple unresolved issue affecting all MacPro 2009 owners.

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Without creating a long and boring post - for months MacPro 2009 customers are experiencing overheating and performance issues see macrumors- Audio Processing Causing Heat and performance Issues for Nahalen Mac Pros - when it is noted that if you open up iTunes and play a song the CPU temps rise alarmingly along with power consumption while Activity Monitor shows a mere 1% usage. The problem has been highlighted by Ars technika url http://redirectingat.com/?id=292X457...ying-audio.ars
(Hope I am allowed to post this link)

Many owners of these computers have raised the issue with Apple who in their usual inimitable fashion deny any knowledge of the problem stating that the temp rise is within the normal parameters of the Nahalen Chip. Running iTunes on other Macs and earlier models of the MacPro this problem does not happen.

The annoying factor is that with the CPU temperature rise there is a large increase in wattage, and these MacPro 2009 are described as "expensive room heaters" - no joke... A MacPro running windows (bootCamp) does not have the problem indicating that it is more likely an OSX software issue

A young hacker involved in the hackintosh scene believes the problem is related to the driver that controls newer features of the Nehalem Xeons, including SpeedStep and Turbo Boost. He generated a hacked power management kernel extension that disabled these features, which eliminated the high heat and power draw issues while playing audio. With SpeedStep disabled, however, the CPU drew more power at idle, and the sleep function is disabled.

The main Apple kext responsible appears to be AppleIntelCPUPowerManagement.kext - attached. We have so many experts here and I for one would be very grateful as to any new ideas as to what might be causing this problem which is unique to all versions of the MacPro 2009.

Thanks

Are there any guys here who might be interested in taking this on.

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NB This is something that AsereBLN could easily address if he were interested, as he has done so much research into speedstepping and C-states.

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Fixed by Apple on Thursday 11th February 2010 by software update after the prob was raised on Ars technica and CNET.

AudioAUUC:

Version: 1.4
Last Modified: 2/9/10 8:10 PM
Kind: Intel
Architectures: i386, x86_64
64-Bit (Intel): Yes
Location: /System/Library/Extensions/AudioAUUC.kext
Kext Version: 1.4
Load Address: 0xffffff7f810b7000
Valid: Yes
Authentic: Yes
Dependencies: Satisfied


Build 10.6.3 10D552 installed and Loaded on real MacPro 2XQuad Core Nahalen 2.26

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More info via a young hacker known as Cindori on MacForums.

The original fix that Apple distributed via sofware update supposed applicable to OSX 10.6.2 was fixes to two kext files - AppleHDA.kext and IOPlatformPluginFamily.kext.

Cindori isolated the fixed kexts and has distributed these as a zip file "audiofix". I have loaded these texts using Kext Utility.app, repaired permissions and all seems fine.

The IOPlatform kext fix is likely due to noted temperature rises on macPros when attaching to USB and firewire external drives.

All credit please to Cindori