The SNK Neo GEO CDZ was released in Japan on Dec 29th, 1995 as the replacement upgrade for SNK's previous "front loader" and "top loader" Neo Geo system consoles. The Neo Geo CD had been criticized previously for slow loading times that could vary from 30 to 60 seconds between loads, depending on the particular game. SNK of Japan felt they could continue to maintain profitable sales while competing against Playstation in the Japanese home market by shortening the previous system's load-times.
It was widely rumored that the CD-ROM drive speed was increased from 1x to 2x. The truth, however, is that the CDZ had a larger amount of system memory cache. Though the CD-ROM motor in the CDZ was a more efficient model over the original, it was still a 1x speed CD-ROM. It was the cache that sped up load times in CDZ.
Like most next generation systems this system can run hot and proper ventilation is needed for longer play times.
The Neo Geo CDZ lacked a "region lock" so it is considered Region Free and could play older CD software.