Apple Releases Fix for Mac Pro Overheating Problem
Apple has just released a software fix for a problem on 2009 Mac Pros with Nehalem-based Intel Xeon processors. The bug caused a 20 percent performance hit when playing audio in Mac OS X, and also caused CPU temperatures to double. Mac Pro Audio Update 1.0 is available for download from Apple
, and requires Mac OS X 10.6.2.
Mac Pro users found that when they played music on iTunes, Activity Monitor would report just 1 to 3 percent CPU load, but CPU power draw will increase as much as ten times normal. At the same time, CPU temperatures, which are normally about 30°C while idling will rise up to 60°C or higher - near what Intel rates as the Nehalem chip's safety limit - with little or no fan activity. The problem could also be triggered by plugging in FireWire or USB-based audio interfaces.
The Mac Pros with Nehalem Xeon were introduced in March 2009 with a 2.66 GHz quad-core processor. In December, the 3.33GHz quad-core model was added to the lineup. Though users with both models of Mac Pro have reported the issue, the download page and the knowledge base article
on the Mac Pro Audio Update says that it is specifically for computers that were released in the first half of the year.
A similar issue has also been reported on 27-inch iMacs
, in particular when using Logic Studio software. Unlike in the case of the Mac Pro, however, the iMac fans run: in some cases up to 2800 RPM, causing considerable noise.