CDZ
Yes, it has a 2x CD drive, which is used at 2x speed. Loading times aren't exactly cut by 2 when comparing to older models due to fixed delays caused by CPU data copy.
It is obvious that SNK anticipated the possibility of integrating the CD drive's electronics directly onto the motherboard. This apparently has never been done.
NEO-GRC2 made by Fujitsu
See optical pickups
Sanyo LC89513 CD host chip, able to do 4x speed by the way:
Z80, its RAM and 1MiB PCM DRAM:
Same weird voltage limiting power supply circuit:
System ROM: TOP-SPD.
Unpopulated fotprint for CD drive chips:
