After getting a few beach-balls today, I checked the Activity Monitor and was shocked to see that it was only reporting 3GB RAM instead of 4GB (I have 2x1GB Techworks RAM and 2x2x512MB Apple OEM RAM). I next checked he System Profiler and it was showing that I have six 512MB sticks in there, and that all the RAM is OK. I ran TechTool and it did not find anything wrong with the RAM. I removed the Apple RAM and reseated the two 1GB sticks several times, but they're still being recognized as 512MB. Anybody have any idea what could be going on? If the RAM is bad, would it not simply fail to be recognized altogether?