Neo-Geo AES
The Neo-Geo AES was a consoleized version of the Neo-Geo MVS developed and produced by SNK.
Details
The AES started out as a rental only system for hotel chains. Consumer interest in the console rose and thus SNK released the AES for home use on January 31st 1990. Debuting in the USA at $649, the console came with two joystick controllers and a choice of a game, either Baseball Stars Professional or NAM-1975. Unlike the Super NES and Genesis, home ports ran on the same code as the arcade games giving the player an authentic arcade experience.
Later on the system would be offered as a "Silver" package for $399 which contained one controller and no game. Games for the Neo Geo AES were priced at $200 and up. The high prices kept the AES out of the mainstream though a cult following remains to this day.
Hardware
Using the popular Motorola 68000 clocked at 12 Mhz and a Zilog Z80A clocked at 4 Mhz, the AES had more power than other consoles from the time period. Although it was sometimes marketed as a 24 bit system, the Neo Geo AES is in reality a 16 bit system with an additional 8 bit processor. The AES featured 64KB RAM, 74KB VRAM, and 2KB Sound Memory.
The AES has a resolution of 320×224. It can display 4096 on-screen colors out of a palette of 65536, double the palette featured in the Super Nintendo.
Like the Neo-Geo MVS the AES ran on rom cartridges. The original spec allowed up to 330Mb of data to be stored on a cartridge but as programmers got more experience with the console the counts increased finally resulting in a 716Mb (89.6MB) cartridge.
Software
Programming / Hacking details.
Mods
Audio
Bios
Since almost all game cartridges contain both arcade and home version code as well as both Japanese and English versions you want to exchange the bios in your unit with a universal bios where you can switch between modes and regions. It also allows cheats, jukebox functionality, pause, soft reset and a few other useful features. The Unibios can be ordered from here. Keep in mind that the bios is a DIP that needs to be either desoldered or that you piggyback upon it.