Specifications

The first column in Table 4-1 (page 61) shows the memory size of the largest DIMM with that device size that

the computer can accommodate. The third column specifies the number of devices needed to make up the

8-byte width of the data bus. The fourth column in the table shows the size of each bank of devices, which is

based on the number of internal banks in each device and the number of devices per bank.

Table 4-1 Sizes of DDR SDRAM expansion DIMMS and devices

Size of each bankDevices

per bank

Device configurationSDRAM device sizeSize of DIMM

64 MB84 M x 8 x 4128 Mbits128 MB

64 MB42 M x 16 x 4256 Mbits128 MB

128 MB84 M x 8 x 4128 Mbits256 MB

128 MB44 M x 16 x 4256 Mbits256 MB

256 MB88 M x 8 x 4256 Mbits512 MB

512 MB816 M x 8 x 4512 Mbits1 GB

RAM Addressing

Signals A[0–12] on each SDRAM DIMM make up a 13-bit multiplexed address bus that can support several

different sizes of SDRAM devices. Table 4-2 (page 61) shows the address multiplexing modes used with the

devices.

Table 4-2 Address multiplexing modes for SDRAM devices

Size of column addressSize of row addressDevice configurationDevice size

10124 M x 8 x 4128 Mbits

9122 M x 16 x 4128 Mbits

10138 M x 8 x 4256 Mbits

9134 M x 16 x 4256 Mbits

10148 M x 8 x 4512 Mbits

Expansion

RAM Expansion