Basics Dual In-Line Memory Modules (DIMMs) - 33

Dual In-Line Memory Modules

(DIMMs)

The 5400 series and 5500 use DRAM Dual In-Line Memory
Modules (DIMMs) instead of DRAM Single In-Line Memory
Modules (SIMMs). Whereas SIMMs have 72 pins, DIMMs
have 168 pins. The extra pins provide a 64-bit data path,
compared to a 32-bit data path for SIMMs. In addition,
DIMMs do not have to be installed in pairs like the SIMMs on
earlier Macintosh models.

Important:

The SIMMs used in previous Macintosh models
are

not

compatible with the 5400 series or the 5500. The
5400 series requires DIMMs with refresh rate of 2K.