Amount of available storage on the module. If there are parenthesis shown – for example (2 x 4GB) – it indicates a kit of 2 or more identical modules is used to reach the Total Capacity.
Number of modules. Memory can be installed as single modules or in kits comprised of 2 or more identical modules. Each module requires its own slot for installation.
Memory spec terms
If you're not sure if a module is right for your system, use the Crucial Memory Advisor tool for a list of guaranteed compatible modules.
NON-ECC/Non-parity Most desktop and laptop computers take NON-ECC or Non-parity memory.
ECC/Parity ECC or parity modules look for errors in data and are most often found in servers and other mission-critical applications used by large networks and businesses.
Unbuffered Most PCs and workstations use unbuffered memory which is faster than registered memory.
Registered/Buffered Registered or buffered modules delay all information transferred to the module by one clock cycle. This type of memory is primarily used in servers.
Fully buffered Designed for next-generation servers, features an advanced memory buffer.
CL CAS (column address strobe) latency, which is the number of clock cycles it takes before data starts to flow after a command is received. Lower CL is faster. Modules with different CL can be mixed on a system, but the system will only run at the highest (slowest) CL.
Component configuration (For example: 64Meg x 64) Indicates the size of the memory chip components on the module.
Voltage For example 2.6V. Indicates the power used by the module. The lower the better.
A dual inline memory module (DIMM) consists of a number of memory components (usually black) that are attached to a printed circuit board (usually green). The gold pins on the bottom of the DIMM provide a connection between the module and a socket on a larger printed circuit board. The pins on the front and back of a DIMM are not connected to each other.
184-pin DIMMs are used to provide DDR SDRAM memory for desktop computers. Standard 184-pin DIMMs are available in PC1600 DDR SDRAM, PC2100 DDR SDRAM, PC2700 DDR SDRAM, and PC3200 DDR SDRAM.
To use DDR memory, your system motherboard must have 184-pin DIMM slots and a DDR-enabled chipset. A DDR SDRAM DIMM will not fit into a standard SDRAM DIMM socket. (Information about which memory technology your system uses is included in the Crucial Memory Advisor™ tool.)
The number of black components on a 184-pin DIMM can vary, but it always has 92 pins on the front and 92 pins on the back, for a total of 184. 184-pin DIMMs are approximately 5.25 inches long and 1.25 inches high, though the heights can vary. While 184-pin DIMMs and 168-pin DIMMs are approximately the same size, 184-pin DIMMs have only one notch within the row of pins.