The Atari 400 and 800 were the first home computers to use custom coprocessors and the first to use "sprites" and special video interruptions like display lists; features that would be implemented later on the Commodore 64, then on the Commodore Amiga (Atari 400/800 and Amiga were both designed by Jay Miner).
It offered high graphic resolution, lots of colors and great sound capabilities, more than other computers could do then! The two models had same characteristics, but the 800 had 48 KB of RAM (instead of 16 kb), two cartridge ports (only one for the 400) and a proper mechanical keyboard (a membrane keyboard for the 400).
In fact the very first Atari 800 Computers were shipped with 8 or 16 KB memory, expandable to 48 KB. After initial release, the 800 came standard with 48 KB memory.
Prior to production, the 800 was known inside Atari as code name "Colleen". It is rumored that Colleen and Candy (the 400 code name) were actually secretaries at Atari.
END OF PRODUCTION
QWERTY full Stroke keyboard, 62 keys 4 function keys (Reset, Option, Select, Start)
ANTIC (Scrolling, Sprites, Video), CTIA / GTIA (Color, Sprites, Collisions), POKEY (timers, sound, keyboard, serial I/O), PIA 6810 (I/O, including the 4 joystick ports)
8 KB to 48 KB (with memory expansion boards)
40 x 25
several graphic modes, maximum : 320 x 192
16 (each color can have 8 luminances) = 128 colors maximum in the lowest graphic mode (requiring display list interruption to have them simultaneously) and up to 256 colors in some specific modes for machines having the GTIA chip instead of the CTIA
4 voices, 3.5 octaves
SIZE / WEIGHT
40.5 (W) x 33 (D) x 11 (H) cm / 4200 g
Monitor RGB output, RF TV video output, 2 cartridge slots, Atari Serial Input/Ouput (SIO) port, 4 controller jacks, 4 internal slots for memory modules