For recordable discs, the process is permanent and the media can be written to only once. While the reading laser is above all not stronger than 5 mW, the writing laser is considerably more powerful. The tertiary school writing speed, the less epoch a laser has to warmness a mite on the media, thus its endowment out-of-date to augmentation Cassette to CD Recorder proportionally. DVD burner's laser often peaks at about 100 mW in continuous wave, and 225 mW pulsed.

Some drives further lower their maximum read speed to around 40x on the reasoning that blank discs will be clear of structural damage, but that discs inserted for reading may not be