The games he is talking about are Yagawa games and are programmed completely differently from most other Cave games on that hardware. They use a special compressed graphics format to be able to fit inside the graphics rom and decompress on the fly at certain parts which stresses the shit out of the CPU. During the other parts of the game the CPU is generally not the bottleneck and slowdown is programmed in rather than the CPU maxing out. For the greater parts of games Naomis are stressing the CPU more than Caves.