As you can see, they're virtually identical with the exception of the manufacturing date and ES mark. Both chips are marked -6ns which means 166.67MHz clock speed, 333.33MHz data rate because these are DDR chips. The DIMM has 16 of these chips, 8 on each side and it is a double sided module, for a total of 256MB, which means that each chip can store up to 16MB (128Megabits or 16MegaBytes) each.