Hard Disk Speeds

There are a lot of urban myths promulgated about disk speeds. Someone recently asserted that it was vital to have one disk for your operating system and a separate hard disk for your video. Not true - as you yourself can demonstrate as shown here.

Providing that you set up your system correctly, and you do proper disk housekeeping, any 5400rpm hard disk produced in the last two years or so will provide you with all the speed you require - and here I will explain why this is so. Even better - if your hard disk is older than two years, by using the information given here you can determine if it is adequate for video work.

Firstly though, I'll give you a link to free software, Sandra, that you can use to analyse the performance of your hard disk. To give you the assurance of problem-free disk reads and writes for video editing or CD/DVD burning all you have to do is this:

Determine the Buffered Read and Buffered Write benchmark for your own particular drive, using Sandra.
Divide the above benchmark figures by 3.6MB/s to give you the overhead factor that you do have to support video work.

Sandra can be downloaded and installed from: http://www.3bsoftware.com/downloads/sandra/sandrap.html

To get your hard drive benchmarks double-click on File System Benchmark
Select the drive to be tested from the pull-down menu,

To get an accurate figure don't use your mouse or keyboard while the tests are carried out.

The figures you should be looking at are the buffered read and buffered write. Divide these figures by 3.6MB/s. Why 3.6MB/s ?

DV requires 3.6MB/s - which is the speed at which the video comes off your camcorder's tape, and the speed at which it will be writted to your hard drive. If your hard drive can write this data at this speed you won't have problems. Similary, if you are writing back to your camcorder's tape using DV-in, providing that you can read data from your hard drive at this speed you'll have no problem. The last scenario is associated with the speed at which you can read/write from your CD-RW or DVD burner. You can check this too with Sandra providing you first put a 64MB (or larger) file onto a CD (or DVD). Needless to say, however, your CD or DVD drive will read/write much more slowly than you can write/read respectively to/from your hard disk - so again you won't have any problems.

Having hopefully proven to you that you don't need a separate 7200rpm hard drive for your video, there are, however, advantages in having one:

Rendering and Making Movie operations in your favourite video editor will be faster.
Defragging your video hard disk will be faster, because video files (being larger) don't introduce fragmentation to the same degree as on your system/program/non-video data disk.