Eh, if I can remember correctly, the Wiz's cpu is an ARM926EJ-S while the DS's cpus are a ARM946E-S and a ARM7TDMI.
The Arm9 (67mhz) on the DS is used for graphics rendering and game logic. The Arm7 (33mhz) is used for processing sound output, wifi,
and when the DS is in GBA mode it does what...