
Still no joy trying to figure out why my iMac only recognizes 256 MB of a 512 MB memory card. I have a service call placed to the RAM vendor to see what they advise.
On the good side, I bravely opened the rest of the iMac shell to find the other piece of RAM. The people and web sites I had consulted previously greatly overstated how difficult it was to get to the DIMM: only an extra layer of shielding and electronics needed to be removed to gain access. Imagine my surprise to find that the internal primary DIMM is not only utterly different RAM format from the secondary SoDIMM, but also it's the same type my older XP box utilizes.
Alas, my XP machine only has 256 MB DIMMs so swapping them into the primary RAM slot wouldn't help the iMac. I ordered two 512 MB DIMMs for the XP machine last Saturday and they should arrive any day now... I could plunk one immediately into the iMac to increase its memory while I get the secondary SoDIMM issue sorted out. I'm currently bidding on an additional 512 MB DIMM on eBay (currently $20) so the XP box will get fully upgraded eventually.
Who knew this minor RAM upgrade would become such a pain in the ass? True, this is the sort of system engineering foolishness which keeps me gainfully employed, which probably explains why I have this cumpulsion to shower every time I delve into these kinds of issues...