Neo Geo CD

The Neo Geo CD was released in 1994, four years after its cartridge-based counterpart, in an effort to reduce manufacturing costs. The system was originally priced at $300 brand new. The unit's 1x CD-ROM drive was slow, making loading times very long with the system loading up to 56 Mbits of data between loads. Neo Geo CD games retail at $50, in contrast to the Neo Geo AES game cartridges which cost as much as $300. The system could also play audio CDs.

The Neo Geo CD comes with a control pad instead of the joystick. This made the controls more stiff and caused some difficulty in play, if one was used to the joystick.

The Neo Geo CD failed to sell well, mainly because of a lack of marketing, in addition to the introduction of more powerful game consoles capable of producing 3-D polygon graphics.

Models
Three versions of the Neo Geo CD have been released:
 * A "front-loading" version (only distributed in Japan, 25,000 total units were built)
 * A "top-loading" version that was marketed worldwide (the most common model)
 * The Neo Geo CDZ, a redesigned version of the console featuring a faster 1x CD drive.

Neo Geo CDZ
The Neo Geo CDZ was released in 1996 as the Japanese market replacement for the Neo Geo CD. The Neo Geo CD had met with limited success because it was plagued by slow loading times that could vary from 30 to 60 seconds between levels, depending on the game. Although SNK's American home entertainment division quickly acknowledged that the system simply wasn't capable of competing with 3D-capable powerhouse systems of the day like the Sega Saturn and Sony PlayStation, SNK corporate of Japan felt they could continue to maintain profitable sales in the Japanese home market by shortening the previous system's load-times.

Popular rumor suggests that SNK made several changes to the CD hardware to end up with the CDZ, most prominent is the rumor that they increased the CD-ROM drive speed from 1x to 2x. The truth of the matter, is that the CDZ had a larger cache. Though the CD-ROM motor in the CDZ may have been more efficient than the one in the original, it was still a 1x speed CD-Rom. The console had a design flaw that sometimes caused it to overheat after certain periods of time, breaking the console in the process and making it hard to repair. This was a result of a lack of ventilation in the cramped housing of the smaller unit and more heat generated by the newer drive, which could damage the circuit board.

Availability
The CDZ console was the third of three generations of the Neo Geo CD system offered by SNK, the first two being the "front-loader" CD system and the "top-loader" CD system. Like the original front-loading model Neo Geo CD system, the CDZ was officially sold only in Japan during its production. However its lack of a "region lock-out" feature and the fact that it could play games from other regions made it a popular import item for enthusiasts in Europe and North America. Today, they can be found sporadically on the internet, especially through auction sites such as eBay.

Technical Specifications:

 * Main Processor: Motorola 68000 running at 12 MHz
 * Although the 68000 CPU was designed by Motorola, there were many other clones of this CPU found in the Neo Geo hardware. The most common CPU is the TMP68HC000 manufactured by Toshiba. This is essentially a Motorola 68000 clone.
 * Co-Processor: Zilog Z80 running at 4 MHz
 * Colors On Screen: 4,096
 * Colors Available: 65,536
 * Resolution: 304x224
 * Max Sprites: 380
 * Max Sprite Size: 16x512
 * Number of Planes: 3

The system is also capable of reading Redbook standard Compact Disc audio.

In addition to the multi-AV port (exact same one as used on the Sega Genesis model 1), all Neo Geo CD models had composite RCA A/V and S-Video out jacks on the rear of the console.

The CD system's 58 Mbit / 7 MB of RAM was split accordingly:


 * 68000 Program Memory: 2 MB
 * Fix Layer Memory: 128 KB
 * Graphics Memory: 4 MB
 * Sound Sample Memory: 1 MB
 * Z80 Program Memory: 64 kB


 * VRAM: 512Kb (For graphics attributes)
 * SRAM: 2 KB (For high scores/general save data)