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EuphangeLGR 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)
  • EuphangeLGR Level 1 (0 points)
    The model of the FireWire chipset my macbook is equipped with is LSI (Lucent / Agere) FW643 (FW800, PCI ID 5901) Revision 6
  • EuphangeLGR Level 1 (0 points)
    Also, id like to notice that its not a manufacturer's driver fault because even with the drivers uninstalled, OSX loads up AppleFWAudio and the spikes are the same, regardless if the manufacturer's drivers are installed or not
  • EuphangeLGR Level 1 (0 points)
    Firewire Audio disconnected / or AppleFWAudio.kext unloaded = Idle temp arround 50 celcius (iStat)

    Firewire Audio Connected with AppleFWAudio.kext loaded = Idle temp arround 60 celcius (iStat)

    If theres a possibility that this is due to bus powered firewire device (cause i have an external FW hard drive that is self-powered and temps are not rising when i connect it) then AppleFWAudio.kext maybe manages something with bus powered firewire.

    Maybe when i have the interface connected but the kext not loaded the mA sucked by the interface are too little for causing a temp rise but by the time the kext is loaded and the interface is converting audio the mA required tops up so the temp rise comes from the mA load on the firewire bus and not the cpu itself.

    *Even if that's the case, the rapid spikes of throttling on the cpu by the time the Firewire Audio interface is connected bothers me. This isn't something that should normaly happen on an idling machine.*
  • eww Level 9 (52,980 points)
    EuphangeLGR: This is probably something you should be discussing directly with AppleCare and with Apogee, since there is clearly an odd relationship between the two pieces of hardware and the Apple and Apogee software that mediates between them. The fact that there have been no responses here suggests that no one else reading the forum is using the same combination of equipment or experiencing the same problem with it.
  • EuphangeLGR Level 1 (0 points)
    Actually there are a lot people reports temperature rise with FW audio interfaces but they consider this normal and there are also people reporting this as an issue (google firewire audio heat). I definetely dont think that this is something to do with Apogee. I have already talked with them and they also stated that this must be something Apple extensions-level related.

    Im pretty sure the same spikes are also happening with other FW audio interfaces. Im gonna try to test a different one, even self powered

    Thanks for the reply
  • EuphangeLGR Level 1 (0 points)
    What i've just found:

    Run Geekbench latest version with firewire interface unplugged: ~3580 score
    Run Geekbench latest version with firewire interface plugged: ~3480 score

    There is a 100 points decrease when my firewire interface is connected.

    Tested with and without apogee drivers, with and without CoolBook enabled, with 10.6.3 and with 10.6.4. Same results

    Info: 10.6.4 updates AppleFWAudio.kext but doesn't seem to change anything

    Any comment on that?
  • eww Level 9 (52,980 points)
    Euphangel: You're doing some fine testing, but I'll say again that it appears no one else who is reading this forum shares your problem. That doesn't mean no one shares it, but if anyone does, they aren't posting here about it. So I think you need to talk to Apogee and Apple. You aren't reaching anyone here who can help you.
  • EuphangeLGR Level 1 (0 points)
    I've talked to Apogee, this isn't someting about their driver nor device related. Its clearly about Apple and AppleFWAudio

    I've sent a bug report with and will wait for an official answer. Actually, i find it good for other people and future reference to be able to google search and find these threads

    Thanks for your reply!
  • JosephAB Level 1 (0 points)
    I have the same fan problem with my Macbook and Duet. The fan ramps up to 6000 rpm and stays there. Apogee said it is a problem with Leopard on some macbooks that also happens with other Bus Firewire devices.

    Apple needs to fix this issue. It is hard to get a good recording when your mics pick up all the noise from the fan. I am considering upgrading to Snow Leopard to see if that relieves the problem. Any one know?
  • thegreatcurve Level 1 (10 points)
    Snow Leopard doesn't help, sadly. I have this issue with my late 2007 MacBook and a Presonus FireBox.
  • JosephAB Level 1 (0 points)
    I just submitted info to apple about the problem here:
  • borad Level 1 (5 points)
    same problem here with a brand new 2010 mbp. temperature normally around 50°, with my focusrite saffire le pugged in its between 65° and 70°. it's not only hot, the system is getting slow as well after some hours with the interface connected. it also took me a while to relate this to my firewire interface, since i just bought it a week ago to replace my old mbox1 (which was usb). i was looking foreward to this upgrade a lot but now it turns out to be some kind of downgrade in terms of performance. i hope this will soon be solved.
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