The early 286 and 386 pc98s released from 1987-89 and sold some time after (mine was made in late 1990) had a unique feature: a v30 and 286/386 cpu. Turning the machine off and moving switch sw3-8 allows you to choose which cpu you want to start the machine with. Instead of turbo mode here's a full on different cpu, and both share the same io devices. However you can see the 640k of base ram on the motherboard and the extra ram on the cpu board with the 386. Both the graphics chips and io chips are on the mainboard.