The problem some encounter..the FSB changes from 400MHz to 333MHz. So some users simply avoid the problem by installing all of their RAM in 2 slots....if they want 2GBs total...they install 2-1GB DIMMs vice 4 -512MB DIMMs. Check your motherboard manual for further info.
That you should only install 2 sticks of ram?? I have 4 sockets (2x512) + (2x256), but I have heard that it is better to use just 2 sticks. Is this true?