Amiga 4000 - Sept 1992 (Commodore)
A4000/040 A4000/030
In 1992 September Commodore released the successor of the A3000 based around the AGA chip set. The first models were equipped with 040 processors only, later - to fill the gap between the A1200 and the A4000/040 - with 030 processors too. Apart from the used processor cards the two models are identical.

68030 @ 25-50 MHz 68040 @ 25-40 MHz 68060 @ 50 MHz PowerPC 604e @ 150-233 MHz
Most desktop A4000s' processor is located on a removable processor card. The A4000/040 originally shipped with the A3640 featuring a 68040 or 68LC040 @ 25 MHz, and the A4000/030 with the A3630 featuring a 68EC030 @ 25 MHz and a socket for an optional 68881 or 68882 floating point unit. Some late A4000/030 has its processor soldered to the motherboard leaving the CPU slot empty.

up to 2 MB Chip RAM up to 16 MB Fast RAM on motherboard up to 128 MB Fast RAM on processor cards up to 1 GB Fast RAM on Zorro III expansion cards
Most A4000s have five 72 pin SIMM sockets on their motherboard - one for Chip RAM, the other four for Fast RAM. The sockets accept industry standard 32 or 36 bit page mode SIMMs. The four parity bits of the 36 bit modules are ignored and they function as simple 32 bit ones. EDO RAM is not supported by the motherboard RAM controller, Ramsey, but some processor cards accept it and some even use its benefits.
The Chip RAM socket has to be filled with either a 1 or 2 MB SIMM. The four Fast RAM sockets accept 1, 4 or 8 MB modules up to a total of 16 MB Fast RAM. The SIMMs cannot be mixed and the 8 MB ones have to be placed in every second socket. Late models have the four Fast RAM sockets only. The fifth socket is missing, it is replaced by 2 MB 70 ns Chip RAM soldered to the motherboard. The access speed of the Fast RAM on the motherboard can be controlled by software, either 80 or 60 ns.

Custom chips
Alice - AGA display controller
Lisa - AGA display encoder
Paula - audio and I/O controller
Fat Gary - system address decoder
Super Buster - DMA arbitrary controller
Ramsey - RAM controller
Bridgette - complex buffer
Click for external site!