ZX Spectrum Memory Map Explorer

Explore the memory layout of the ZX Spectrum and see how the CPU address space, physical RAM, dynamic memory areas and hardware expansions interact. Select a Spectrum model and use the controls below to change the memory configuration.

Main CPU Memory Map

Hover over the map

Move your mouse over a memory area to see its address range and information.

Memory Key

CPU Memory

ROM

◥ ZX Interface 1 Shadow ROM

Display File

Attribute File

ZX Printer Buffer

System Variables

128K Paging / System Area

Contended RAM

Uncontended RAM

Unavailable – No Physical RAM

Dynamic Areas

BASIC Program

Variables

Character Set – 768 bytes

UDGs

Calculator Stack

E-LINE

Dynamic areas are overlays showing where the Spectrum's system variables indicate that areas of memory are being used.

In 128K mode, the CPU map shows ROM 0/1, RAM 5, RAM 2 and the paged RAM area. Individual RAM-bank selection is not modelled in Version 1.

Spectrum Model

Address Format

ZX Interface 1

Shows the additional Interface 1 system variables and the resulting shift of dynamic RAM areas. The Shadow ROM is switched in only when required.

ZX Printer

Reserves the printer buffer area on 16K and 48K models. Not applicable to 128K mode.

Adjust Dynamic Memory

BASIC Program (PROG)

Variables (VARS)

E-LINE

STKEND

WORKSP

STKBOT

RAMTOP

CLEAR address

Stack Pointer (SP)

UDG Address

CHARS Value

Page Revised: 20/08/2026