SUMMARY

This article discusses the difference between a dual in-line memory module (DIMM) and a single in-line memory module (SIMM), and it identifies which Power Macintosh computers use DIMMs.

MORE INFORMATION

SIMM

SIMMs are installed in pairs on the original Power Macintosh 6100-, 7100-, and 8100-series computers. These 72-pin, 80 nanosecond or faster SIMMs, have a 32-bit wide internal data path. The data bus is 64-bits wide on these computers. Two SIMMs are required to accommodate this data bus.

The Power Macintosh 5200 series computers have a 32-bit wide data bus that can be installed one SIMM at a time. The 5200 series computers have two SIMM slots. Additional memory can be added by filling the other slot with one 72 pin, 70 nanoseconds or faster SIMM.

DIMM

A DIMM provides a wider data path than a SIMM. Therefore, DIMMs are "wider" than SIMMs in the amount of data they can carry.

The Power Macintosh 7200-, 7500-, 8500-, and 9500-series computers use 168- pin, 70 nanoseconds or faster DIMMs which are 64-bits wide. It takes one DIMM to meet the 64-bit wide data bus requirement. The Power Macintosh 7500-, 8500-, and 9500-series computers also support memory interleaving when DIMMs are installed in pairs. The Power Macintosh 7200- series computers do not support memory interleaving and can be installed one DIMM at a time.

REFERENCES

This information was provided by Support Information Services Copyright 1995, Apple Computer, Inc.