All Namco games are done on the System series...
SC1 = System 12
SC2 = System 246
SC3AE = System 246
Tekken 2 = System 12
Tekken 3 = System 246
Tekken 4 = System 246
Tekken 5 = System 256
System 246 and 256 are based on Playstation2 architecture... which is why SC3 only came out on the PS2. Laziness from Namco, they didn't want to have to port the game over to two other systems, so they just left it on the core.
Dreamcast and Naomi FTW...