System slowdown due to errant FireWire devices
System slowdown due to errant FireWire devices
We're beginning to investigate an issue where some Macs experience significant slowdown due to errant, connected FireWire devices. The causal link is established when a user disconnects or disables a FireWire device and performance returns to normal immediately.
In many cases, the problem worsens as more data is transferred between the system and device.
MacFixIt reader Jack Howell writes:"I just bought my Mac Pro and use with it a Cubase 4, and a MOTU 896HD audio interface. Oddly, when I first turn everything on, it works very well. But, the longer it runs, the slower it seems to get. As soon as I disable the Firewire audio interface, the system returns to it's normal pace. I have to have this interface in order to conduct my business. All literature out there suggests that the Mac Pro works with Cubase and MOTU.
"I'm not sure what to do at this point. I've run all the tests there are to run on the Mac. It appears to be running normally. I have all the newest drivers and software updates as well."
Though further scrutiny is required, it appears that this issue is due to faulty interaction between the FireWire device controller chipsets used in some devices and one or more of the IOFireWire kernel extensions located in /System/Library/Extensions.
In some cases, clearing specific kernel-related caches can temporarily alleviate symptoms of this issue. You can use a utility like Tiger Cache Cleaner, or manually delete the following files:
- /System/Library/Extensions.kextcache
- /System/Library/Caches/com.apple.kernelcaches
Feedback? Late-breakers@macfixit.com.
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