Problems with RAM We continue to cover an issue where the Power Mac G5 Uniprocessor firmware update makes some units more picky about RAM -- that is, modules that previously functioned properly now cause operational problems including system freezes. In some cases, the culprit RAM is identified by Apple's Hardware Test CD, which is included with all G5s.
In MacFixIt reader Neville Thomas' case, the the problem-RAM was the original factory installed module. He writes:
"I installed the firmware update on my Power Mac G5 1.6 GHz model. Immediately problems starting occurring. The modem started disconnecting but never completed, ending in a freeze. The mouse and keyboard became useless, but on advice I ran (the Apple Hardware Test CD) and it reported one bad RAM card It was one of two original RAM cards. (Would you believe this was 2 days outside the 12 month warranty?)
"I removed that pair of cards and moved the additional (non-original) memory cards up one slot. [...] Was the RAM always bad?"
Thomas' case in particular begs the questions: are these RAM modules, which apparently functioned without incident prior to the firmware update the potential root of other issues, and only recognized as faulty thanks to the update? Or are they innocuous until the the firmware update is applied?
Switching RAM modules to different slots As previously reported, switching the location of RAM modules has resolved this issue for a number of readers. Specifically, moving the inner DIMMs to the outer slots, the outer DIMMs to the inner slots.
While you are switching modules around, make sure that they all meet the following requirements:
- 2.5 volt
- 184-pin module
- Maximum number of memory devices on DDR SDRAM:16.
- No error correcting codes (ECC)
- Unbuffered (registered or buffered DDR SDRAM cannot be used)
Knowledge Base article #86414 contains further information on installing and working with G5 RAM.
Fix on the way? One poster to Apple's Discussion boards says he had a discussion with Apple's technical support department, who indicated a fix was on the way.
Matthew Dioguardi writes "I updated my G5 1.6 like so many others here and have been experiencing problems with my computer. Audio is funny, keyboard freezes, random crashes, kernel panics, etc.
"I called Apple Japan today (I live in Japan.) The support person asked me to sit tight as Apple was working very hard on this. She was noncommittal and would not tell me if the solution was going to be a hardware or a software one. She acknowledged that switching RAM around and so on were potentially temporary solutions. But she stopped short of recommending I do it.
"She seemed optimistic that the solution would come in the form of a new firmware update. [...]
"I asked her about how long it would take for a solution, days, weeks, months. She could not say. I made her give me a case number and told her I would call back in a few days unless a solution was made available on the support page."
Getting replacement RAM Meanwhile, it appears that some manufacturers (possibly including Apple) might be willing to replace RAM modules that are causing problems after the firmware update.
Another poster to Apple's Discussion Boards, Marek Helsner, says he received the following (paraphrased) response from Apple:
"The firmware update sets the specs for the RAM closer so some of them will not work after the update. This depends on the manufacturer and/or the date of manufacture. This explains why for some users it works fine and for others it causes this mess. Anyway, in the case of the RAM breakdown apple will send new ram for free and all you do is ship back the damaged ones after receiving the new ones."
If you are covered under an Apple warranty or through the Apple Care program and are experiencing problems with Apple-supplied, original RAM, you may want to try contacting the appropriate department for a possible replacement.Feedback? Lateemail@example.com.Resources