The SpeedTools ZoneBench is a benchmarking application designed to measure the read and write speeds over an entire local storage device. That device can be either logical (such as a disk volume which is actually a RAID array made up of two or more disk drives) or physical (such as your internal ATA disk drive). ZoneBench also has the capability to measure the speed of read-only devices such as mounted CD and DVD data discs.
Audio-visual content creation professionals will likely find ZoneBench a particularly useful tool to evaluate the minimum throughput requirements of their video capture storage devices. The target speed overlay feature was designed specifically for a quick reference tool to verify your device's minimum speed requirement. A target speed overlay is a white line or semi-opaque rectangle (if you are using a safety margin) which is drawn superimposed over the results graph on the main window. The line corresponds to the target speed measured in Megabytes per second.