I have a 20" Intel Core 2 Duo 2.16GZ 667 MHz with 2 512 MB DDR2 SDRAM (SO DIMM) PC2-5300 In my manual it also says Unbuffered and Unregistered. I want to add more memory I have researched and found Kingston memory but it says nothing about unbuffered ad unregistered. Also I see that some of the memory sticks state 200 or 240 pin I do not see anywhere in my manual or about this Mac on my apple icon about this mac. I need some help as I do not want to order the wrong one. I have checked negegg and omepcworld.com.