Amstrad CPC vs Sinclair ZX Spectrum: 8-Bit Screen Architecture Compared
Compare the video display hardware, memory mapping, and graphics capabilities of the Amstrad CPC (CRTC 6845) and Sinclair ZX Spectrum (ULA).
The Amstrad CPC and Sinclair ZX Spectrum were fierce 8-bit rivals in Europe throughout the 1980s. The CPC featured 16KB of video RAM powered by the Motorola 6845 and Gate Array with flexible 160×200, 320×200, and 640×200 modes, while the ZX Spectrum used an iconic 6,912-byte 256×192 display with 8×8 color attribute clash.
| FEATURE | CPC | ZX SPECTRUM |
|---|---|---|
| Video Display Controller | Motorola 6845 CRTC + Amstrad Gate Array | Sinclair Custom ULA (Uncommitted Logic Array) |
| VRAM Buffer Size | 16,384 bytes (16 KB) | 6,912 bytes (6.75 KB) |
| Standard Resolutions | 160×200 (Mode 0), 320×200 (Mode 1), 640×200 (Mode 2) | 256×192 |
| Hardware Color Palette | 27 discrete colors (3 levels per RGB channel) | 16 colors (8 normal + 8 bright intensity) |
| Color Artifacts | None (individual bitplane pixels) | Attribute clash (max 2 colors per 8×8 pixel cell) |
- Flexible graphics modes: Mode 0 (16 colors), Mode 1 (4 colors), Mode 2 (monochrome 640x200)
- No attribute clash: every pixel has its own dedicated color bits
- Rich 27-color Gate Array hardware palette with pastel shades
- 16KB dedicated video buffer with hardware scrolling support
- Extremely compact 6,912-byte screen footprint (6,144 bytes bitmap + 768 bytes attributes)
- Higher default horizontal resolution (256 pixels vs CPC Mode 0's 160 pixels)
- Massive game software library and vibrant modern homebrew scene
- Instant loading and low CPU overhead on Z80 processors
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