KB10010: Amiga Models Compared – A1000 to A4000 and Beyond

The Commodore Amiga line ran from 1985 to 1996, producing some of the most technically advanced home computers of their era. The platform's strength came from its custom chipset architecture—dedicated coprocessors for graphics, sound, and I/O that offloaded work from the main CPU. Understanding which chipset generation a model uses is the key to understanding the entire Amiga family.

Chipset Generations

Every Amiga discussion starts with the chipset. There were three generations:

• OCS (Original Chip Set) – Agnus, Denise, and Paula. Supported up to 32 colors on screen from a 4,096-color palette in standard modes, with a special HAM (Hold-And-Modify) mode capable of displaying all 4,096 simultaneously. Four channels of 8-bit PCM stereo audio. Found in the A1000, A500, and A2000.
• ECS (Enhanced Chip Set) – Upgraded Agnus (Fat Agnus/Super Agnus) and Super Denise. Added productivity display modes (640×480 and higher), Super Hi-Res mode, and support for more chip RAM (up to 2 MB). Found in the A500+, A600, and A3000.
• AGA (Advanced Graphics Architecture) – Alice and Lisa replaced Agnus and Denise. Expanded the palette to 16.8 million colors (24-bit), with up to 256 colors on screen in standard modes and 262,144 in HAM-8 mode. Doubled sprite resolution. Found in the A1200, A4000, and CD32.

Amiga 1000 (1985)

The original. Designed by Jay Miner's team, the A1000 debuted the Amiga architecture with a Motorola 68000 CPU at 7.16 MHz (NTSC) or 7.09 MHz (PAL). It shipped with 256 KB of RAM, later bumped to 512 KB. The A1000 was unique in loading Kickstart (the operating system kernel) from floppy disk into a special 256 KB write-protected RAM area on every boot—later models had Kickstart in ROM. It featured a front-panel expansion slot, a side expansion bus, and a detached keyboard. The A1000 is the most collectible Amiga model today, partly due to low production numbers and the signatures of the design team molded inside the top case.

Amiga 500 (1987)

The A500 was the mass-market Amiga, packaged as an all-in-one keyboard unit similar in concept to the Commodore 64. It used the same 68000 at 7 MHz and OCS chipset as the A1000, but shipped with 512 KB of RAM (expandable to 1 MB via the trapdoor expansion on the bottom). A side expansion port allowed for additional memory and peripherals. The A500 became the best-selling Amiga model worldwide, especially in Europe where it dominated the gaming market. It ran Kickstart 1.2 or 1.3 from ROM.

Amiga 500+ (1991)

A short-lived revision that upgraded the chipset to ECS, bumped the base RAM to 1 MB, and shipped with Kickstart 2.04 and Workbench 2.0. The ECS upgrade and new Kickstart caused compatibility problems with some older games that relied on OCS-specific behavior or Kickstart 1.3 quirks, which frustrated consumers. The A500+ was primarily sold in Europe.

Amiga 2000 (1987)

The A2000 was the expandable desktop Amiga, aimed at professional and enthusiast users. It used the same 68000/OCS foundation as the A500 but in a full desktop case with five Zorro II expansion slots, two PC ISA-compatible bridgeboard slots, a CPU card slot, and a video slot. Standard RAM was 1 MB. The Zorro slots accepted a wide range of expansion cards—RAM, hard drive controllers, network cards, video capture, and more. The CPU slot was particularly important, as it allowed accelerator cards with 68020, 68030, or even 68040 processors to dramatically upgrade performance. Various revisions exist (A2000-A, A2000-B, A2000-CR) with minor motherboard differences.

Amiga 3000 (1990)

The A3000 was a significant leap forward. It featured a Motorola 68030 CPU at 16 or 25 MHz (depending on model), the ECS chipset, and a new motherboard design with 32-bit Zorro III expansion slots (backward compatible with Zorro II cards). Standard RAM was 2 MB of chip RAM and 1 MB of 32-bit fast RAM, expandable on the motherboard. It included a built-in SCSI hard drive controller, a flicker fixer for scandoubled output to VGA monitors, and an improved power supply. The A3000 ran Kickstart 2.0 and AmigaOS 2.0, which brought a significantly improved Workbench and Intuition UI. A tower variant (A3000T) was also produced.

Amiga 600 (1992)

The A600 was a compact, cost-reduced model intended to replace the A500 at the low end. It used the 68000 at 7 MHz with the ECS chipset and 1 MB of chip RAM. Its most notable features were a PCMCIA Type II slot (for memory cards and compact flash adapters, making it popular for modern storage upgrades) and a 2.5-inch IDE hard drive bay. However, Commodore controversially removed the numeric keypad and the internal expansion slot used by the A500, reducing its expandability. The A600 ran Kickstart 2.05. It was not well-received at launch due to being seen as a step backward from the A500+ in terms of expandability while not being a significant step forward in performance.

Amiga 1200 (1992)

The A1200 brought the AGA chipset to the consumer keyboard-unit form factor. It used a Motorola 68EC020 CPU at 14 MHz—the first 32-bit processor in a consumer Amiga—with 2 MB of chip RAM. The AGA chipset dramatically improved graphics capabilities: up to 256 colors in standard modes, 262,144 colors in HAM-8, and support for 16.8 million color values in the palette. Like the A600, it had a PCMCIA slot and 2.5-inch IDE bay, plus a 150-pin local bus expansion port on the bottom for accelerator cards (allowing 68030, 68040, or 68060 upgrades). The A1200 ran Kickstart 3.0 and remains one of the most actively used Amigas in the retro community due to its good balance of capabilities and expandability.

Amiga 4000 (1992)

The flagship desktop Amiga combined the AGA chipset with a Motorola 68040 CPU at 25 MHz (the A4000/040) or a 68EC030 at 25 MHz (the lower-cost A4000/030). It featured Zorro III expansion slots, a CPU card slot for accelerators, 2 MB of chip RAM, up to 16 MB of fast RAM on the motherboard, an IDE hard drive controller, and flicker fixer output. A tower version (A4000T) followed with additional drive bays and expansion room. The A4000 ran Kickstart 3.1 and represented the pinnacle of Commodore-produced Amiga hardware before the company's bankruptcy in 1994.

Amiga CDTV (1991)

The CDTV (Commodore Dynamic Total Vision) was essentially an A500 in a set-top-box case with a CD-ROM drive, infrared remote control, and no keyboard (though one could be attached). It used the 68000 with OCS and 1 MB of RAM. Commodore marketed it as a multimedia appliance rather than a computer. It was a commercial failure, caught between markets—too expensive for consumers, too underpowered for the computer market.

Amiga CD32 (1993)

The CD32 was a game console based on the A1200's AGA architecture with a 68EC020 at 14 MHz, 2 MB of chip RAM, and a double-speed CD-ROM drive. It was the world's first 32-bit CD-ROM-based game console. It included Akiko, a custom chip that accelerated chunky-to-planar graphics conversion. The CD32 achieved modest success in Europe but Commodore's financial collapse in 1994 cut its life short. With a keyboard adapter and expansion, a CD32 can function as a basic A1200.

Quick Comparison Table

Model	Year	CPU	Chipset	Base RAM	Form Factor
A1000	1985	68000 @ 7 MHz	OCS	256 KB	Desktop
A500	1987	68000 @ 7 MHz	OCS	512 KB	Keyboard unit
A500+	1991	68000 @ 7 MHz	ECS	1 MB	Keyboard unit
A2000	1987	68000 @ 7 MHz	OCS	1 MB	Desktop (expandable)
A3000	1990	68030 @ 16/25 MHz	ECS	2 MB	Desktop (expandable)
A600	1992	68000 @ 7 MHz	ECS	1 MB	Compact keyboard unit
A1200	1992	68EC020 @ 14 MHz	AGA	2 MB	Keyboard unit
A4000	1992	68040 @ 25 MHz	AGA	2 MB	Desktop (expandable)
CDTV	1991	68000 @ 7 MHz	OCS	1 MB	Set-top box
CD32	1993	68EC020 @ 14 MHz	AGA	2 MB	Game console

Collector and Restoration Notes

Electrolytic capacitor failure is the single biggest issue across all Amiga models. The A500, A600, A1200, and CD32 are particularly prone to capacitor leakage that corrodes traces on the motherboard. Early recapping is strongly recommended before leaking capacitors cause irreversible damage. On the A2000 and A4000, the battery-backed real-time clock uses a barrel battery (often a Varta NiCd) that is notorious for leaking acid onto the motherboard—inspect and remove these immediately. Power supplies on all models should be tested before use. The custom chips (Agnus, Denise, Paula, and their later variants) are not reproduced and are becoming scarce.