In Search of True DDR2 Bleeding Edge Memory

DDR2 Parts Details

Typical module sizes for DDR2 RAM are 512 MB and 1 GB. DIMMs with 256 MB or 2 GB are somewhat harder to find on the market. Uninformed buyers are sure to be confused by the many and varied memory speed designations, shown in the following table.

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DDR2-1066533 MHzPC8000
DDR2-888444 MHzPC7100
DDR2-800400 MHzPC6400
DDR2-711355 MHzPC5700
DDR2-667333 MHzPC5300
DDR2-533266 MHzPC4200
DDR2-400200 MHZPC3200

Additional information about placement of individual memory chips on a module and their organization.

Most memory makers offer precise information about what chips they use in their modules.

The designation: "Chip: 64Mx8" means that individual chips on a module consist of eight 64-megabit memory parts (64 megabits / 8 bits per Byte = 8 MegaBytes or MB = 64 MB total). By extension, each individual chip has a storage capacity of 64 megabits.

The designation: "Module: 128Mx64" indicates that the entire module includes 64 parts, each 128 megabits in size (128 megabits / 8 bits per Byte = 16 MB x 64 parts = 1 GB). If a 1 GB module is composed of 16 individual chips, each chip must therefore have 64 MB of capacity. In this case, we're talking about double-sided modules, because when it comes to large-capacity chips only eight typically fit on each side of a standard memory module.

Typical configurations for desktop DDR2 memory modules are:

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Module CapacitySidesTypical Chip Organization
256 MB132 MB Chip x 8
512 MB232 MB Chip x 8 x 2 Sides
512 MB164 MB Chip x 8
1 GB264 MB Chip x 8 x 2 Sides
1 GB1128 MB Chip x 8
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