In the 1990's SNK decided that it was time to jump into the home and arcades with its new 24 bit system. Technically, the console was a 16 bit system that used an 8 bit co-processor. The main processor was the Motorola 68000, and the co-processor was the Zilog Z80A. Even though the Z80A was used mostly for audio processing, it was used from time to time to assist the main processor. Some have even claimed that the system was nothing more than a "glorified Sega Genesis" since some of the internals weren't much different.
The Neo-Geo AES utilized a custom video chipset that allowed the system to draw sprites in vertical strips at 16 pixels wide, and 16 to 512 pixels tall. The GPU in the system set it apart from other consoles on the market at the time, as it offered colors, animation, details, and effects that weren't found on the competing 16 bit consoles of the time.
The Neo-Geo was an interesting concept at the time. The home versions of the arcade games were one and the same. The differences were the pin outs for them. This was so arcade operators couldn't use the "less expensive" home versions in the arcade cabinets. The arcade system (MVS) was also one of a "rarity" at the time where gamers could bring in their memory cards from home, plug them into the arcade machine, and continue a game they were playing at home at the arcade.
The console was actually rather popular, even with its hefty price tag. SNK expanded their reach by releasing less expensive packages of the console. Later, SNK released the Neo-Geo CD. The CD version was the same as the AES unit, but used CD's that cost US$50, rather than the expensive cartridges that would run at US$200 and up. This proved unsuccessful for the most part due to the single speed (1x speed) CD-ROM drive. This meant that games loaded excruciatingly slow.
Many popular titles has been released over the years. These include Fatal Fury, Samurai Showdown, Metal Slug, The King of Fighters, and World Heroes. Some of these titles continue to find success today.
The Neo-Geo was discontinued in 1997, and technical support lasting as long as 2007. The last official home cartridge release was in 2004. In 2012, Tommo released the Neo-Geo X. This was a licensed handheld that utilized SD cards to store Neo-Geo games. It used emulation to achieve its end result, and not using miniaturized hardware based on the original console. However, emulation was relatively well done, and games played as they were intended. That unit sold for US$199.99. Interestingly, the unit could be docked inside of a Neo-Geo AES replica dock that allowed the user to play the console on a television, and use a replica of the original arcade style joystick.