CD-ROW/R/RW and DVD Speed Test
This test (part of PerformanceTest), allows the data read speed from a CD or DVD drive to be measured. Measuring the write speed to CD-Rs and CD-RWs is also available on Windows 2000, XP and 2003 Server. Vista and Windows 7 use a different write method that is not yet supported as of PT 7.0.
The rate at which a CD Drive can read data from a CD ROM varies about many factors. Firstly, and most importantly, is the speed of the manufactured drive. Older drives list speeds of 2X or 4X, (1X = 0.1536 MB/Sec), whereas top end drives at time of writing are now advertised as having speeds of 48X and 56X.
Another large influence on the data transfer rate from CD/DVD is the system cache and the part it plays in storing frequently accessed data. The cache is a section of memory Windows uses to store data for fast access. The first time, for instance, a 10 MB file is read from a CD / DVD ROM, it is likely that Windows will copy it to the cache, recognizing that the data may soon be requested again. Upon subsequent requests for the same file, Windows will simply read the file directly from the cache and hence bypass the bottleneck of reading from the CD/DVD ROM again. If the data hasn't been used, after a certain period of time and/or a certain number of I/O requests, it will be replaced in the cache with more recent or essential data. Requesting the file at this stage, will mean Windows must go directly to the CD/DVD ROM once more. Obviously, whether the file data on the CD/DVD ROM is cached or not, has a large impact on tests which use the cache.
The Advanced CD/DVD test allows users to change the following test parameters.
- The size of the data block used for each read request. Larger blocks mean less requests and can lead to an improvement in performance (CD-ROM test)
- The choice of four access methods - CLIB, WIN32 API cached/uncached and raw disk access (CD-ROM test).
- The duration to carry out the test for.
The results of all completed CD ROM, CD-R and CD-RW speed tests may be graphed using our colourful custom graphing components.