Spectrum 48K
- Processor
- Zilog Z80A
- Clock
- 3.5 MHz
- Sound
- One-bit beeper, one channel
- Launch
- 1982
8-bit computer comparison — ZX Spectrum specs side by side
Most playground arguments about these machines were settled without an 8-bit computer comparison specs table to hand. Pick any two and read the twelve rows; some arguments settle and others get considerably worse.
| Specification | Machine A | Machine B |
|---|
What this 8-bit computer comparison does not tell you
Three places where an 8-bit computer comparison specs table misleads, and the reasons why.
The first is the Acorn Electron. On paper it carries the same processor and the same 2 MHz clock as the BBC Micro Model B, and it is slower in practice because one custom chip arbitrates video and memory together. Any 8-bit computer comparison that stops at the clock speed gets this wrong, which is why the table carries a note on the row.
The second is price. Machines were sold in different configurations, and the Amstrad CPC 464 included a cassette deck and a monitor in its headline figure while the ZX Spectrum and the Electron were sold bare. The comparison shows the published price and states what it covered rather than silently normalising the numbers.
The third is colour. The ZX Spectrum lists fifteen colours and applies them per character cell rather than per pixel, which is a hard constraint that shaped an entire visual style. A specs row reading “15” conveys none of that, so the note does.
Spectrum 128
- Processor
- Zilog Z80A
- Clock
- 3.5 MHz
- Sound
- General Instrument AY-3-8912, three channels
- Launch
- 1986
BBC Micro B
- Processor
- MOS 6502A
- Clock
- 2 MHz
- Sound
- Texas Instruments SN76489, three tone channels and one noise
- Launch
- 1981
Electron
- Processor
- MOS 6502A
- Clock
- 2 MHz
- Sound
- One channel
- Launch
- 1983
ZX Spectrum, BBC Micro and Acorn Electron — all eight machines, specs in full
The full set the comparison draws on, with what each one was for.
ZX Spectrum 48K
The machine that put a colour computer in the largest number of British bedrooms, and the one whose limitations shaped a whole visual style.
- Processor
- Zilog Z80A at 3.5 MHz
- Memory
- 48 KB RAM, 16 KB ROM
- UK launch
- £175, 1982
ZX Spectrum 128
The same screen, four times the memory and a real sound chip — a late upgrade that gave the format another four years of software.
- Processor
- Zilog Z80A at 3.5 MHz
- Memory
- 128 KB (paged) RAM, 32 KB ROM
- UK launch
- £179, 1986
BBC Micro Model B
The expensive, well-built one. A 2 MHz 6502 and a proper keyboard, bought by education authorities and coveted by everyone whose school had one.
- Processor
- MOS 6502A at 2 MHz
- Memory
- 32 KB RAM, 32 KB ROM
- UK launch
- £399, 1981
Acorn Electron
Acorn’s attempt at a home-priced BBC Micro. Software-compatible in principle, noticeably slower in practice, and the machine this archive keeps coming back to.
- Processor
- MOS 6502A at 2 MHz
- Memory
- 32 KB RAM, 32 KB ROM
- UK launch
- £199, 1983
Commodore 64
Hardware sprites, scrolling and the SID chip. The Spectrum’s opposite number in every playground argument of the decade.
- Processor
- MOS 6510 at 0.985 MHz (PAL)
- Memory
- 64 KB RAM, 20 KB ROM
- UK launch
- £399, 1982
Amstrad CPC 464
The fastest Z80 here and the widest palette, sold as one box with the tape deck built in. Bought by families who wanted the whole thing settled in one purchase.
- Processor
- Zilog Z80A at 4 MHz
- Memory
- 64 KB RAM, 32 KB ROM
- UK launch
- £249 with a green screen, £359 with colour, 1984
Dragon 32
Welsh-built, technically interesting, and starved of software. The cautionary tale of the British micro boom.
- Processor
- Motorola MC6809E at 0.89 MHz
- Memory
- 32 KB RAM, 16 KB ROM
- UK launch
- £199, 1982
Oric-1
Better sound than the Spectrum, cheaper than the Electron, and remembered mostly for how hard it was to load a game.
- Processor
- MOS 6502A at 1 MHz
- Memory
- 16 KB or 48 KB RAM, 16 KB ROM
- UK launch
- £129 for 16 KB, £169 for 48 KB, 1983
Questions about the comparison
What the figures are, and where they stop being comparable.
Which machines does this 8-bit computer comparison cover?
Eight: the ZX Spectrum 48K and 128, the BBC Micro Model B, the Acorn Electron, the Commodore 64, the Amstrad CPC 464, the Dragon 32 and the Oric-1. Any two can be set side by side across twelve specification rows.
Why do the BBC Micro and the Acorn Electron have the same clock but different speed?
Because the Electron routes both video and memory access through a single custom chip. In the graphics modes that chip holds the processor off the bus for part of every cycle, so identical code runs measurably slower on the Electron than on the BBC Micro it was derived from.
This is the single most useful thing in the table, because the specs alone suggest the two machines should perform alike and they do not.
Are the launch prices in this comparison directly comparable?
Not always, and the table says so where they are not. The Amstrad CPC 464 price includes a built-in cassette deck and a monitor, whereas the ZX Spectrum and Acorn Electron prices are for the machine alone. Comparing the headline numbers without that context overstates how expensive the Amstrad was.
Where do these specs come from?
They are published launch specifications — what the manufacturer stated when the machine went on sale. They are not measured benchmarks, and the comparison does not present them as such.
Unit-sales figures are deliberately excluded. They are not reliably established for most of these machines and would have been the weakest claim on the page.
Which machine had the best sound?
On specs, the Commodore 64. Its SID chip offers three voices with filtering against the ZX Spectrum 48K’s single-channel beeper, and it manages that on the slowest processor in the table — which is the whole trade-off in one row.