http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=84738&CatId=554

Will this stick of ram work? Apple says the max is 640mb so will a 1gb stick work? I've got a 12" powerbook 867mhz.

Yes, it will work. The Apple-posted maxmium was correct at the Powerbook's release, but is no longer the maxmium as of currently; however, I'd recommend you buy a PC-2700 (333 MHz) RAM instead, as PC-2100 (266 MHz) RAM is less reliable according to people's experiences.

Why was this correct at its release but no longer correct today. If his book was manufactured to those specs, should it not stil be governed by the initial restrictions? or is Maximum allowed RAM a function of the OS rather than the mother board

Why was this correct at its release but no longer correct today. If his book was manufactured to those specs, should it not stil be governed by the initial restrictions? or is Maximum allowed RAM a function of the OS rather than the mother boardEither that or 1 GB SO-DIMM's didn't exist at the time of his Powerbook's release. Just like the iMac DV slot-loading models - the Apple posted maximum is 512 MB - but we all know they can easily 1 GB of RAM and not just 512 MB. The reason for this is because the iMac only has 2 RAM slots, and at the time of its release, DIMM's larger than 256 MB in size didn't exist, therefore making the max 512 MB. Since then, 512 MB DIMM's hit the market, increasing the iMac's maximum amount. Heck, there's even speculation that the iMac can actually hold 2 GB of RAM, made up of 2x1 GB DIMM's under Mac OS X.