Editing Macintosh IIfx (section)

=== Memory Configuration ===

The IIfx uses eight 64-pin SIMM slots arranged in two banks:

{| class="wikitable styled-table" style="width:85%; text-align:center;"
|+'''Memory Bank Configuration'''
! Configuration !! Bank A (4 slots) !! Bank B (4 slots) !! Total RAM !! Notes
|-
| Factory minimum || 4 × 1 MB || Empty || 4 MB || Standard configuration
|-
| || 4 × 1 MB || 4 × 1 MB || 8 MB || Common upgrade
|-
| || 4 × 4 MB || Empty || 16 MB || Single bank populated
|-
| || 4 × 4 MB || 4 × 1 MB || 20 MB || Mixed configuration
|-
| || 4 × 4 MB || 4 × 4 MB || 32 MB || Popular configuration
|-
| || 4 × 8 MB || 4 × 8 MB || 64 MB || Unofficial support
|-
| Maximum || 4 × 16 MB || 4 × 16 MB || 128 MB || Requires 16 MB SIMMs
|}

'''Memory Specifications:'''
* '''Type:''' 64-pin proprietary SIMMs
* '''Speed:''' 80ns or faster required
* '''Data path:''' 8-bit wide per SIMM (32-bit total per bank)
* '''Architecture:''' Dual-ported with separate read/write paths
* '''Parity:''' Optional 9-bit SIMMs for error checking
* '''Installation:''' Must populate in sets of four matching SIMMs

'''Important Notes:'''
* Although the IIfx uses the same type of 64-pin SIMMs as the LaserWriter IINTX, you cannot use memory from the printer in the IIfx – the printer memory is not fast enough for the Mac IIfx.
* Bank A sockets are furthest from front panel
* Bank B sockets are nearest to front panel
* Drive assembly must be removed for RAM access