I recently purchased a Rev. C PowerBook (arrived today) and tried putting the 512MB PC2100 DDR266 SDRAM from my Rev. A into it, and it isn't recognizing it. I checked the manual and it said that in order for my Rev. C to take the RAM is has to be PC2700. I've heard, though, that people have used generic RAM in PoweBooks (like that Fry's deal), so... I'm confused.