Sega’s advertising positioned the Genesis as the cooler console,[56] and coined the term blast processing, an obscure and unused graphics programming method, to suggest that its processing capabilities were far greater than those of the SNES.
Damien McFerran. “Retroinspection: Mega-CD”. Retro Gamer. Vol. 61. London, UK: Imagine Publishing. p. 84. During the run-up to the Western launch of Mega-CD … [Former Sega of America technical director Scot Bayless] mentioned the fact that you could just ‘blast data into the DACs’. [The PR guys] loved the word ‘blast’ and the next thing I knew ‘Blast Processing’ was born."
Per Wiki:
So, a bunch of smoke and mirrors.
I like how Claymates made fun of it with “blaze processing.”