Hardware Reference
In-Depth Information
mounted on both sides of the module, and dual-rank modules can have chips physically
mounted on only one side. I recommend using the terms
single rank
or
dual rank
instead,
because they are much more accurate and easily understood.
Figures 6.6
through
6.12
show a typical 30-pin (8-bit) SIMM, 72-pin (32-bit) SIMM, 168-pin
SDRAM DIMM, 184-pin DDR SDRAM (64-bit) DIMM, 240-pin DDR2 DIMM, 240-pin DDR3
DIMM, and 184-pin RIMM, respectively. The pins are numbered from left to right and are connected
to both sides of the module on the SIMMs. The pins on the DIMM are different on each side, but on a
SIMM, each side is the same as the other and the connections carry through. Note that all dimensions
are in both inches and millimeters (in parentheses), and modules are generally available in ECC
versions with 1 extra ECC (or parity) bit for every 8 data bits (multiples of 9 in data width) or
versions that do not include ECC support (multiples of 8 in data width).
Figure 6.6. A typical 30-pin SIMM.
Figure 6.7. A typical 72-pin SIMM.
