The "SEGA" chant at the beginning of the Genesis game Sonic the Hedgehog took up 1/8th of the cartridge's space!

The old bleeps and bloops of old video game music might be technologically outdated, but they still have a huge number of fans who enjoy the way it sounds. However, when Sonic the Hedgehog was in development, SEGA really wanted to show that the Genesis was superior to their biggest rival, the Super NES.

They wanted to position the Genesis as being the cooler console between that and the Super NES. To do this, they used a bunch of marketing tricks, like saying that SEGA Genesis had "Blast Processing," which made games better on the Genesis. History is murky on this, but most people seem to think it was mostly a marketing trick. 

Although we're speculating a bit here, putting real sound in the intro of the game was probably part of their strategy to look technologically superior to their rival. SEGA decided to use the SEGA chant that was in their commercials in the intro to Sonic. It came at a price, though. The sound reportedly took 1/8 of the 1/2 Megabyte capacity of the cartridge!

(Sources 1, and 2)