In my titanium G4 Powerbook, the memory doesnt add up to what is installed. Inside the actual computer there are two cards: a 512MB and a 256MB. However system profiler says there the 256 is infact a 128... SO instead of 768, I only have 640MB. I have taken the memory out and re-inserted it, but when the computer starts up you get constant kernal panics. After a while it stops freezing, but when you goto system profiler it once again only shows 640MB.