DriveSpace can dramatically increase your available disk space. However, because DriveSpace uses at least 33K of memory, it makes sense not to install DriveSpace unless you need it. Most files contain a lot of repeated data. When DriveSpace finds repeated data in a file, it retains the first occurrence of that data, and replaces any other occurrences of that data with a cross-reference to the first occurrence. The cross-reference takes less space than the original data.
Some files contain more repeated data than others.
Bitmap files and text files typically compress well, since most such files contain a lot of repeated data. If you have a computer with a fast CPU and a fast hard disk, you probably won't notice much difference in system speed after installing DriveSpace. If you have a fast CPU and a slow hard disk, DriveSpace might actually improve your system's speed. If your computer has a slow CPU, you may notice a reduction in speed after compressing your drive. DriveSpace Setup configures your computer to run DriveSpace and compresses the drive of your choice.