The Commodore Amiga 4000, or A4000, is the successor of the A2000 and A3000 computers. There are two models, the A4000/040 released in October 1992 with a Motorola 68040 CPU, and the A4000/030 released in April 1993 with a Motorola 68EC030.
The A4000 is housed in a white desktop box with a separate keyboard. Later Commodore released an expanded tower version called the A4000T.
Unlike previous Amiga models, early A4000 machines have the CPU mounted in an expansion board; the motherboard does not have an integrated CPU. Later revisions of the A4000 have the CPU and 2 MB RAM surface-mounted on the motherboard in an effort to reduce costs. These machines are known as the A4000-CR (Cost Reduced) and the surface mounted CPU is a 68EC030. The cost reduced models also made use of a non-rechargeable lithium battery for real-time clock battery backup rather than a rechargeable NiCd battery. The NiCd backup battery is one of the most common causes of problems in an aging A4000 because it has a tendency to eventually leak. The released fluids are somewhat corrosive and can eventually damage the motherboard.