More on the importance of removing "bad" RAM: Installation CD problems

It appears that the Mac OS X install discs included with some recently shipping models utilize a more stringent RAM validity check that previous versions, providing even more reason to ensure - using the Apple Hardware Diagnostic CD - that the memory in your Mac is not faulty.

One MacFixIt reader writes in with a case example:

"I am using a 17" iMac, the first rev. (800 Mhz.) I have not been able to use the supplied startup disk for some time now. After some troubleshooting, I was able to determine that the problem was (most likely) caused by a bad 512 MB RAM chip. When I purchased my iMac I also bought two 512 MB RAM chips from [a vendor] (which I have used for a while and am always very happy with) naively thinking that I'd have access to both of the iMac's RAM slots. Needless to say only one of the chips was used. I found that replacing the chip I had been using with the spare I had fixed the problem. Anyone experiencing this problem may want to try removing any third party RAM they have installed."

"I had also been experiencing frequent kernel panics. This was the reason I needed to do a reinstall and also the reason I ended up switching out the RAM chip."

So if you are having problems booting up from the Mac OS X startup disk supplied with your system, try running the Apple Hardware Diagnostic CD, and then removing RAM modules one by one to see if the problem manifests again.

For reference, see our earlier story titled The importance of removing "bad" RAM from your Mac.

Feedback? Late-breakers@macfixit.com.

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