Instant Alerts Get email Alerts on stories that match your interest. To choose a keyword, click here. Choose the right expert at the right price, anytime day or night, at PC World Expert Help . The actual speed attained by the DVD-ROM drives we tested depended on what part of the disc they were reading. Most of them spin the disc at a constant angular velocity, maintaining the same rotational speed no matter where the read head is positioned.
Many manufacturers list only the unit's swiftest DVD-ROM speed.
We ran several tests to gauge the real-world performance of the drives in this review. We also tested DVD-ROM performance by measuring how long the drives took to map a trip using DeLorme's Eartha Global Explorer. We ran the same five read tests on the DVD-RAM drives, and we also measured the time each drive took to write and rewrite a 100MB file. It's cool to own the newest, fastest, most powerful device on the market. The Panasonic took 65 seconds to copy 100MB from the inside track of a CD and 36.5 seconds from the outside track.