Mac OS 0 was limited to 1.5 GB of RAM, but OS X removed those limits. Your machine should be capable of addressing 2 GB of RAM (4 512 MB RAM sticks). Apple Knowledge Base http://docs.info.apple.com/article.html?artnum=58434 says 1.5 GB, but it also says each application was limited to 999 MB of RAM, which is an OS 9 limitation, since OS X does dynamic program memory allocation. Mel "It's good sportsmanship to not pick up lost golf balls while they are still rolling." ~ Mark Twain On Jan 1, 2004, at 11:27 AM, JW Holmes wrote: > Can someone tell me what is the maximum memory that a PowerMac G4/ > 450(AGP) running OS X (Panther) can address? > > > Thanks > > JWH