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EuphangeLGR Level 1 Level 1 (0 points)

After a lot of hours of trying to figure out WHY my macbook pro heats up (a lot) when i connect my newly bought Apogee Duet firewire audio interface, i found out that actually what was happening is that there are CPU spikes of extremely short period (so short that Activity Monitor and iStat could not catch) constantly spiking the CPU frequency from 1596Mhz (Idle) to 2572Mhz (Maximum). Apart from the frequency spike there is also a VOLTAGE spike from 1.0v to 1.15.

I know that this is normal due to speedstep technologies and such BUT the rapid spiking and alterations of frequency and voltage ALWAYS happening when i have my Firewire audio plugged is not normal to me. There is nothing else running, everything's idle and i only plug the firewire interface.

Also this is not happening when i restrict OSX from loading AppleFWAudio.kext (either by deleting, moving, renaming it). I connect the firewire audio interface, the leds are illuminating but no heat problem (thats to show you that is not because the interface is self-powered)

Whats going on seems to be similar with the problems occurred after Mac Pro Audio Update to users that was using FW audio devices. They were hearing a sine noise coming from their macpro and propably that was because the same thing was happening. Constant spikes of voltage to the CPU. I dont have a macpro thought so i cant apply the update Apple released for that issue.

Also, my macbook is using Lucent / Agere (LSI) firewire chipset (the particular and known revision 6) but i dont think that this is the cause since Apogee didnt have any problems with the chipset

Info: The app im using to monitor the Frequency and Voltage is CoolBook, can be found here:

MacbookPro5,1, Mac OS X (10.6.3), Late 2008 (2.53Ghz, 4GB Ram, 320GB HDD)
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