iMac Core Duo (#8): More on USB issues: Keyboard, mouse input lost, etc.; Installing RAM in matched pairs
iMac Core Duo (#8): More on USB issues: Keyboard, mouse input lost, etc.; Installing RAM in matched pairs
More on USB issues: Keyboard, mouse input lost, etc. We continue to cover a bevy of USB issues with iMac Core Duo (Early 2006) models.
The most common problem is an issue where the system stop recognizing input from the keyboard and/or mouse after a period of inactivity, including after waking from sleep.
In many cases, users experiencing the problem see the following error message in the system log file:
- AppleUSBUHCI[0x39e1000]::DoIOTransfer - error 0xe000404f queueing request
There are a few kludgy but effective workarounds:
- Unplugging then re-plugging the afflicted devices
- Switching USB ports
- Adding a powered USB hub and connecting the afflicted devices through it
Meanwhile, some users have reported that the only way they were able to resolve the issue was through replacement of the problematic keyboard and/or mouse. Apple has replaced several users' keyboards, so far on a limited basis.
Installing RAM in matched pairs Several readers have inquired regarding whether or not the iMac Core Duo (Early 2006) will see a performance boost from installing SO-DIMMs in matched pairs, as was the case with the iMac G5.
Indeed users can achieve a small performance boost by installing RAM in matched pairs.
Apple's documentation on the subject states:
"The new iMac comes standard with 512MB of DDR2 memory in a single SO-DIMM, leaving one slot open for future memory upgrades. For a performance improvement when working with large files, configure your iMac with up to 2GB of memory. And if both slots are loaded with an equal amount of RAM, you can take advantage of the system's dual-channel memory interface for an additional performance boost."
Feedback? Late-breakers@macfixit.com.
Previous coverage:
- iMac Core Duo (#7): More problems with flash devices; other USB issues
- iMac Core Duo (#6): Video distortion: "Tearing" and other anomalies; Keyboard volume/eject keys fail; more
- iMac Core Duo (Early 2006) (#5): Problems with flash devices
- iMac Core Duo (Early 2006) (#4): Sporadic blue screens
- iMac Core Duo (Early 2006) (#3): Safe sleep available; Problems with iSub
- iMac Core Duo (Early 2006): Problems with installing Intel Mac OS X on FireWire drives; solution
- Apple unveils new iMac with Intel Core Duo: 2-3X faster than iMac G5, shipping today
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