It had a 2X CD-ROM drive instead of the 1X one of the Neo Geo CD. It was overpriced (at $600) since it did not have too much more then the regular Neo Geo CD. The CDZ also had some issues with overheating during its short life span.
Specs:
CPU: 68,000 (16 bit) CPU Speed: 14 MHz Colors On Screen: 4,096 Colors Available: 65,536 Resolution: 320 x 224 Max Sprites: 380 Max Sprite Size: 16 x 512 Number of Planes: 3 Work RAM: 64 kbit Video RAM: 68 kbit Z80 RAM: 2 kbit CD Sound Chip: 13 Channel Yamaha 2610 Chip CD-ROM access speed: 2X