CD Vs. DVD Storage Capacityby Joe Butler
Technology enthusiasts may remember the big push in the 1990s when compact discs began to replace the floppy disk as the preferred method for transporting data from one computer to another. Though larger in size, they could store significantly more info. The next evolution was the DVD, which was the same size but offered about seven times the space. Even though new storage solutions, such as portable USB drives, memory cards or the Internet cloud, have been created, some users still prefer to use shiny discs for everything from music and video files to system backups.
Types of CDs
There are two different types of CDs. CD-Rs are recordable and once data is on it, or burned, it can’t be erased or added to. CD-RW is a disc that can be rewritten to numerous times. CDs also can have a R- and R+ designation, but this refers to how data is recorded, not storage.
According to Hewlett-Packard’s Learning Center, a CD can hold up to 700MB, which works out to be 80 minutes of audio, hundreds of high-quality images and small audio files.
Users have more options for storage and functionality in their DVDs. Along with the same R, RW, R+ and R- choices as CDs, DVDs also can be double-sided, which can double their capacity, and can also hold one to two layers of data. This means a DVD can hold far more data than a CD.
Hewlett-Packard says single-layer, single-sided DVDs can store up to 4.7GB, which can be two hours of high-quality video, six hours of VHS-quality video, six hours of CD-quality audio, and 72 hours of MP3 audio. Single-layer, double-sided DVDs can store up to 9.4GB: four hours of DVD-quality video, 12 hours of VHS-quality video, 14 hours of CD audio and 144 hours of MP3 audio.
Dual-layer, single-sided DVDs can store 8.5GB of data: four hours of DVD-quality video, 11 hours of VHS-quality, 12 hours of CD-quality audio and 120 hours of MP3 data. Dual-layer, double-sided DVDs offer 17GB of data: eight hours of DVD video, 22 hours of VHS video, 24 hours of CD-quality audio and 240 hours of MP3 audio.
PC World reports that in some cases, the stated maximum capacity for DVDs may not be exactly what you receive because some DVD manufacturers use different standards to define their capacities. For instance, a DVD that says 4.7GB may actually store only 4.26GB of data.