The time it takes to wipe a drive is limited by the speed of the hardware being wiped, not the software. Each sector on the drive must be overwritten to ensure that the data has been erased. Older drives will take much longer to wipe than newer drives. Larger drives will take longer to wipe than smaller drives.
These numbers will vary by system, wipe pattern, number of drives being wiped at once, and settings chosen by the user.