memory disappeared:

I'm running 9.2.2, and after installing a 4.2.1 firmware update, my memory upgrade that has always worked, has suddenly disappeared. Apple profiler read it as "not compatible". Did I fry my memory?" or is the computer confused? Thanks, as always, for the help.

Unfortunately, that is a known issue: search for these words: firmware update RAM and you'll find item # 60839 I would download the free DIMM First Aid and give that a shot, as well as read the user input on Versiontracker:

great --- thanks for your help! I'm going to try that pronto. hope it takes care of this baffling situation.

One RAM vendor told me, there is actually an Eprom which gets 'burned in' setting the speed initially. But this article by Glen Anderson is interesting. I noticed a speedier system with a newer CL 2 vs the older CL 3 myself. But, don't know anymore specifics on the chips other than that. The CL 3 came from Apple (in the unit)