Thanks I shoulda googled.
But I am still stumped by the SDRAM to DDR2 RAM equivalence?
How can that be.
As I've said, if it starts with DDR, it is a form of SDRAM.
Apple never specified which type of SDRAM, and I had a stick of DDR2 from an old Dell, so I put it in to see what would happen. It hasn't killed the thing, and it increased performance.