V ROM
"Voice" ? 8-bit ROMs containing PCM audio samples in cartridges.
In early games, the ADPCM-A and ADPCM-B samples were split in separate V ROMs. Later, the PCM chip was made to allow both types of data to be mixed in the same ROM(s).
V A ROMs minimum speed: any will do (>2µs).
V B ROMs minimum speed: 250ns (see YM2610 bus timing).