 As video games became more complex (and the size of their code grew), software manufacturers began sacrificing the quick load time of ROM cartridges for the greater capacity and lower cost of optical media.Another source of pressure in this direction was that optical media could be manufactured in much smaller batches than cartridges; releasing a cartridge video game inevitably came with the risk of producing thousands of unsold cartridges.Besides their prominent usage on video game consoles, ROM cartridges have also been used on a small number of electronic musical instruments, particularly electronic keyboards.