|Computer memory comes in standard modules, but there are several standards and
you must be careful to order the correct type of memory for the motherboard or
SBC in your computer.
DIMM is the common name for a memory stick. Memory comes in several
pin counts, and you can only use memory with the correct number of pins
in a particular machine. Note that older memory DIMMs are made in 30-pin,
72-pin, and 168-pin sizes, while most newer machines use 184-pin DDR DIMM
modules. Many notebook PCs commonly use SODIMM 144-pin modules, while
newer notebook PCs use 200-pin DDR SODIMM modules.
Memory is also available in different speeds, which determines whether
the memory can keep up with the speed of your computer. Please check your
owner's manual or contact the manufacturer of your computer to determine the
minimum memory speed your PC requires. It is a good idea for all the memory
modules in your computer to be of the same speed.
Memory speed has been stated in several ways over time, but usually by the
same standard for a particular memory type. For example, DIMM modules are
commonly stated as being "PC100" or "PC133" speed, while DDR modules are rated
as "PC2100" ("PC2700," "PC3200," etc.) or they are shown as "266MHz" ("333MHz,"
"400MHz," etc.). If the speed needed for your system is no longer available,
faster speed memory should work without a problem - your PC simply won't push
the new memory to it's fullest capability.
ECC memory is generally used only by servers. Most PCs use
non-ECC memory, and most of the memory we sell is non-ECC memory.
As a general rule, motherboards and SBCs using Pentium® 4 or Athlon® XP
processors use DDR memory modules (184-pin for desktop PCs, 200-pin for notebook
PCs). Pentium II, Pentium III, Celeron®, Duron®, and Athlon systems usually use
168-pin DIMMs (144-pin SODIMMs for notebook PCs). Older 486, 5x86, Pentium, and
Pentium MMX systems (under 233MHz) usually use 72-pin DIMMs, though these have