Umm this is true that they both had 68000s but the comparison of the Genesis really ended there. The Genesis only had a palette of 512 colors (just like the original Atari ST) and it used the same FM synth chip that the original Atari ST did.. The Z80 chip wasn't used for sound it was used for emulation of the Sega Master System for games developed for that unit, which they were claiming backwards compatibility but not much was ever proven. The Master system adapter used the extra Z80.
The Amiga 500 had Paula which definitely had better sound. Many Genesis games including ones that you see on the a500 were ported from their ST versions..
Just thought I should set the record straight on this..
