I've got a Pismo with a 500Mhz G4 upgraded processor. From what I can see on the panel it was originally a 400Mhz G3. I am trying to max the RAM by putting in two 512Mb SODIMMs. When I check the system profiler it won't recognise the entire 512Mb in the upper slot. It reads it as only 256Mb. The bottom chip reads as 512Mb just fine. Anyone know what's up with that? Am I actually getting 1Gb performance even though the system profiler says 768Mb? Or am I only getting 768 performance because of a read problem? Any help/solution greatly appreciated.